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.DataProtocol.Contracts/Connection/ConnectionChangedParams.cs

@@ -0,0 +1,23 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+namespace Microsoft.SqlTools.DataProtocol.Contracts.Connection
+{
+    /// <summary>
+    /// Parameters for the ConnectionChanged Notification.
+    /// </summary>
+    public class ConnectionChangedParams
+    {
+        /// <summary>
+        /// A URI identifying the owner of the connection. This will most commonly be a file in the workspace
+        /// or a virtual file representing an object in a database.         
+        /// </summary>
+        public string OwnerUri { get; set; }
+        /// <summary>
+        /// Contains the high-level properties about the connection, for display to the user.
+        /// </summary>
+        public ConnectionSummary Connection { get; set; }
+    }
+}