Migrated RenderMvcController and RenderIndexActionSelectorAttribute

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

src/Umbraco.Web.Common/Controllers/UmbracoController.cs

@@ -0,0 +1,23 @@
+using System;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Umbraco.Composing;
+using Umbraco.Core.Cache;
+using Umbraco.Core.Logging;
+using Umbraco.Core.Configuration.Models;
+using Umbraco.Core.Services;
+using Umbraco.Web.Security;
+
+namespace Umbraco.Web.Mvc
+{
+    /// <summary>
+    /// Provides a base class for Umbraco controllers.
+    /// </summary>
+    public abstract class UmbracoController : Controller
+    {
+        // for debugging purposes
+        internal Guid InstanceId { get; } = Guid.NewGuid();
+
+    }
+}