Created Tutorials index page

docs/en/Tutorials/Index.md

@@ -0,0 +1,6 @@
+# Tutorials
+
+## Application Development
+
+* [With ASP.NET Core MVC / Razor Pages UI](AspNetCore-Mvc/Part-I.md)
+* [With Angular UI](Angular/Part-I.md)

docs/en/docs-nav.json

@@ -33,6 +33,7 @@
     },
     {
       "text": "Tutorials",
+      "path": "Tutorials/Index.md",
       "items": [
         {
           "text": "Application Development",