Refactoring around the RepositoryResolver to allow the configuration of repositories and cache providers for each repository.

Added implementation of an infrastructure configuration section.
Added unit tests for the RepositoryResolver to verify that it can resolve all repository types and their configured cache provider.

src/Umbraco.Core/Persistence/Caching/RuntimeCacheProvider.cs

@@ -2,7 +2,6 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Runtime.Caching;
-using System.Threading;
 using Umbraco.Core.Models.EntityBase;
 
 namespace Umbraco.Core.Persistence.Caching