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

src/Microsoft.SqlTools.CoreServices/Properties/AssemblyInfo.cs

@@ -0,0 +1,15 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+[assembly: InternalsVisibleTo("Microsoft.SqlTools.Hosting.UnitTests")]
+[assembly: InternalsVisibleTo("Microsoft.SqlTools.Services.UnitTests")]
+
+// Allowing internals visible access to Moq library to help testing
+[assembly: InternalsVisibleTo("DynamicProxyGenAssembly2")]
+