Remove unused IdGenerator.

src/Volo.Abp/Volo/Abp/Domain/Entities/DefaultIdGenerator.cs

@@ -1,27 +0,0 @@
-using System;
-using Volo.Abp.Guids;
-using Volo.DependencyInjection;
-
-namespace Volo.Abp.Domain.Entities
-{
-    //TODO: No need! Directly use Guid Generator!
-    public class DefaultIdGenerator : IIdGenerator, ITransientDependency
-    {
-        private readonly IGuidGenerator _guidGenerator;
-
-        public DefaultIdGenerator(IGuidGenerator guidGenerator)
-        {
-            _guidGenerator = guidGenerator;
-        }
-
-        public string GenerateStringId()
-        {
-            return GenerateGuid().ToString();
-        }
-
-        public Guid GenerateGuid()
-        {
-            return _guidGenerator.Create();
-        }
-    }
-}

src/Volo.Abp/Volo/Abp/Domain/Entities/IdGenerator.cs

@@ -1,11 +0,0 @@
-using System;
-
-namespace Volo.Abp.Domain.Entities
-{
-    public interface IIdGenerator
-    {
-        string GenerateStringId();
-
-        Guid GenerateGuid();
-    }
-}