Add backers and sponsors from Open Collective

Now your open collective backers and sponsors can to appear directly on your README. 
see how it'll look [here](https://github.com/apex/apex#backers)
[More info](https://github.com/opencollective/opencollective/wiki/Github-banner)
Also add badges on top.

README.md

@@ -11,6 +11,9 @@
 [![GitHub forks](https://img.shields.io/github/forks/JimBobSquarePants/ImageSharp.svg)](https://github.com/JimBobSquarePants/ImageSharp/network)
 [![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/ImageSharp/General?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![Twitter](https://img.shields.io/twitter/url/https/github.com/JimBobSquarePants/ImageSharp.svg?style=social)](https://twitter.com/intent/tweet?hashtags=imagesharp,dotnet,oss&text=ImageSharp.+A+new+cross-platform+2D+graphics+API+in+C%23&url=https%3a%2f%2fgithub.com%2fJimBobSquarePants%2fImageSharp&via=james_m_south)
+[![OpenCollective](https://opencollective.com/imagesharp/backers/badge.svg)](#backers) 
+[![OpenCollective](https://opencollective.com/imagesharp/sponsors/badge.svg)](#sponsors)
+
 
 
 |             |Build Status|Code Coverage|
@@ -126,3 +129,73 @@ Core Team
 - [Anton Firsov](https://github.com/antonfirsov)
 - [Olivia Ifrim](https://github.com/olivif)
 - [Scott Williams](https://github.com/tocsoft)
+
+### Backers
+
+Support us with a monthly donation and help us continue our activities. [[Become a backer](https://opencollective.com/imagesharp#backer)]
+
+<a href="https://opencollective.com/imagesharp/backer/0/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/0/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/1/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/1/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/2/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/2/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/3/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/3/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/4/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/4/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/5/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/5/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/6/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/6/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/7/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/7/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/8/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/8/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/9/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/9/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/10/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/10/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/11/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/11/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/12/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/12/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/13/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/13/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/14/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/14/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/15/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/15/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/16/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/16/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/17/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/17/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/18/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/18/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/19/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/19/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/20/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/20/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/21/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/21/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/22/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/22/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/23/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/23/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/24/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/24/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/25/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/25/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/26/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/26/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/27/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/27/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/28/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/28/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/backer/29/website" target="_blank"><img src="https://opencollective.com/imagesharp/backer/29/avatar.svg"></a>
+
+### Sponsors
+
+Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/imagesharp#sponsor)]
+
+<a href="https://opencollective.com/imagesharp/sponsor/0/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/0/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/1/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/1/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/2/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/2/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/3/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/3/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/4/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/4/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/5/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/5/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/6/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/6/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/7/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/7/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/8/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/8/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/9/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/9/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/10/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/10/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/11/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/11/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/12/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/12/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/13/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/13/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/14/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/14/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/15/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/15/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/16/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/16/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/17/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/17/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/18/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/18/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/19/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/19/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/20/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/20/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/21/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/21/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/22/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/22/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/23/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/23/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/24/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/24/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/25/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/25/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/26/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/26/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/27/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/27/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/28/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/28/avatar.svg"></a>
+<a href="https://opencollective.com/imagesharp/sponsor/29/website" target="_blank"><img src="https://opencollective.com/imagesharp/sponsor/29/avatar.svg"></a>