Initial admin and DR services. (#329)

* Add initial services for admin, tasks, and DR

* Fix up some of the contract interfaces

* Make fields public to allow Json.Net to work

* Fix a couple issues in backup contracts

src/Microsoft.SqlTools.ServiceLayer/Admin/AdminService.cs

@@ -0,0 +1,66 @@
+//
+// 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.Protocol;
+using Microsoft.SqlTools.ServiceLayer.Admin.Contracts;
+using Microsoft.SqlTools.ServiceLayer.Hosting;
+using Microsoft.SqlTools.ServiceLayer.SqlContext;
+using System;
+using System.Threading.Tasks;
+
+namespace Microsoft.SqlTools.ServiceLayer.Admin
+{
+    /// <summary>
+    /// Datasource admin task service class
+    /// </summary>
+    public class AdminService
+    {
+        private static readonly Lazy<AdminService> instance = new Lazy<AdminService>(() => new AdminService());
+
+        /// <summary>
+        /// Default, parameterless constructor.
+        /// </summary>
+        internal AdminService()
+        {
+        }
+
+        /// <summary>
+        /// Gets the singleton instance object
+        /// </summary>
+        public static AdminService Instance
+        {
+            get { return instance.Value; }
+        }
+
+        /// <summary>
+        /// Initializes the service instance
+        /// </summary>
+        public void InitializeService(ServiceHost serviceHost)
+        {
+            serviceHost.SetRequestHandler(CreateDatabaseRequest.Type, HandleCreateDatabaseRequest);
+            serviceHost.SetRequestHandler(CreateLoginRequest.Type, HandleCreateLoginRequest);
+        }
+
+        /// <summary>
+        /// Handles a create database request
+        /// </summary>
+        internal static async Task HandleCreateDatabaseRequest(
+            CreateDatabaseParams databaseParams,
+            RequestContext<CreateDatabaseResponse> requestContext)
+        {
+            await requestContext.SendResult(new CreateDatabaseResponse());
+        }
+
+        /// <summary>
+        /// Handles a create login request
+        /// </summary>
+        internal static async Task HandleCreateLoginRequest(
+            CreateLoginParams loginParams,
+            RequestContext<CreateLoginResponse> requestContext)
+        {
+            await requestContext.SendResult(new CreateLoginResponse());
+        }
+    }
+}