Add v2 of the Hosting Service and build nuget packages for it (#675)

* Port v2 of Hosting service to SqlToolsService
- Renamed project to .v2 so that existing hosted service isn't impacted
- Copied over the CoreServices project which contains ConnectionServiceCore and other reusable services for anything interacting with MSSQL
- Ported unit test project across and verified tests run.

* Nuget package support for reusable DLLs

* Use 1.1 version per Karl's suggestion

* Use correct license URL and project URL

* Use new SMO packages

test/Microsoft.SqlTools.Hosting.UnitTests/ProtocolTests/EventContextTests.cs

@@ -0,0 +1,30 @@
+//
+// 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.Protocol;
+using Xunit;
+
+namespace Microsoft.SqlTools.Hosting.UnitTests.ProtocolTests
+{
+    public class EventContextTests
+    {
+        [Fact]
+        public void SendEvent()
+        {
+            // Setup: Create collection
+            var bc = new BlockingCollection<Message>(new ConcurrentQueue<Message>());
+
+            // If: I construct an event context with a message writer
+            //     And send an event with it
+            var eventContext = new EventContext(bc);
+            eventContext.SendEvent(CommonObjects.EventType, CommonObjects.TestMessageContents.DefaultInstance);
+            
+            // Then: The message should be added to the queue
+            Assert.Equal(1, bc.ToArray().Length);
+            Assert.Equal(MessageType.Event, bc.ToArray()[0].MessageType);
+        }
+    }
+}