Move unused forked code to external directory (#1192)

* Move unused forked code to external directory

* Fix SLN build errors

* Add back resource provider core since it's referenced by main resource provider project

* Update PackageProjects step of pipeline

external/Microsoft.SqlTools.Hosting.v2/Protocol/EventContext.cs

@@ -0,0 +1,32 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Collections.Concurrent;
+using Microsoft.SqlTools.Hosting.Contracts;
+
+namespace Microsoft.SqlTools.Hosting.Protocol
+{
+    /// <summary>
+    /// Provides context for a received event so that handlers
+    /// can write events back to the channel.
+    /// </summary>
+    public class EventContext : IEventSender
+    {
+        internal readonly BlockingCollection<Message> messageQueue;
+        
+        public EventContext(BlockingCollection<Message> outgoingMessageQueue)
+        {
+            // TODO: Either 1) make this constructor internal and provide a test framework for validating
+            //       or 2) extract an interface for eventcontext to allow users to mock
+            messageQueue = outgoingMessageQueue;
+        }
+
+        public void SendEvent<TParams>(EventType<TParams> eventType, TParams eventParams)
+        {
+            messageQueue.Add(Message.CreateEvent(eventType, eventParams));
+        }
+    }
+}
+