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.DataProtocol.Contracts/InitializeRequestWithOptions.cs

@@ -0,0 +1,49 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using Microsoft.SqlTools.Hosting.Contracts;
+
+namespace Microsoft.SqlTools.DataProtocol.Contracts
+{
+    /// <summary>
+    /// Parameters provided with an initialize request with extra options provided by the client
+    /// </summary>
+    /// <typeparam name="TInitializationOptions">
+    /// Type of the initialization options expected from the client, can be any reference type
+    /// </typeparam>
+    public class InitializeParametersWithOptions<TInitializationOptions> : InitializeParameters where TInitializationOptions : class
+    {
+        /// <summary>
+        /// Initialization options provided by the client, can be null
+        /// </summary>
+        public TInitializationOptions InitializationOptions { get; set; }
+    }
+
+    /// <summary>
+    /// Request definition for initialization of the server. This version provides optional extra
+    /// parameters that can be used to pass extra information between client and server during
+    /// initialization. If these extra options aren't needed, use <see cref="InitializeRequest"/>.
+    /// </summary>
+    /// <typeparam name="TInitializeOptions">
+    /// Type to use for extra parameters in the initialize request. These appear as
+    /// <see cref="InitializeParametersWithOptions{TInitializationOptions}.InitializationOptions"/>.
+    /// If these extra options are not expected, but extra response options are, simply use
+    /// <c>object</c> as the type. 
+    /// </typeparam>
+    /// <typeparam name="TInitializeResponse">
+    /// Type to use for the initialize response. Due to VSCode's protocol definition, any extra
+    /// params that should be sent back to the client are defined as dictionary of key/value pairs.
+    /// This can be emulated by defining a class that extends <see cref="InitializeResponse"/> with
+    /// whatever extra params are expected. If no extra options are needed, but extra request
+    /// options are, simply use <see cref="InitializeResponse"/> as the type.
+    /// </typeparam>
+    public class InitializeRequestWithOptions<TInitializeOptions, TInitializeResponse> 
+        where TInitializeOptions : class
+        where TInitializeResponse : InitializeResponse
+    {
+        public static readonly RequestType<InitializeParametersWithOptions<TInitializeOptions>, TInitializeResponse> Type =
+            RequestType<InitializeParametersWithOptions<TInitializeOptions>, TInitializeResponse>.Create("initialize");
+    }
+}