New: Use ASP.NET Core instead of Nancy

Co-Authored-By: ta264 <ta264@users.noreply.github.com>

src/Sonarr.Http/VersionedFeedControllerAttribute.cs

@@ -0,0 +1,27 @@
+using System;
+using Microsoft.AspNetCore.Mvc.Routing;
+
+namespace Sonarr.Http
+{
+    public class VersionedFeedControllerAttribute : Attribute, IRouteTemplateProvider
+    {
+        public VersionedFeedControllerAttribute(int version, string resource = "[controller]")
+        {
+            Version = version;
+            Template = $"feed/v{Version}/{resource}";
+        }
+
+        public string Template { get; private set; }
+        public int? Order => 2;
+        public string Name { get; set; }
+        public int Version { get; private set; }
+    }
+
+    public class V3FeedControllerAttribute : VersionedFeedControllerAttribute
+    {
+        public V3FeedControllerAttribute(string resource = "[controller]")
+            : base(3, resource)
+        {
+        }
+    }
+}