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/ConnectionSummary.cs

@@ -0,0 +1,48 @@
+//
+// 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
+{
+
+    public interface IConnectionSummary
+    {
+        /// <summary>
+        /// Gets or sets the connection server name
+        /// </summary>
+       string ServerName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the connection database name
+        /// </summary>
+        string DatabaseName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the connection user name
+        /// </summary>
+        string UserName { get; set; }
+    }
+
+    /// <summary>
+    /// Provides high level information about a connection.
+    /// </summary>
+    public class ConnectionSummary : IConnectionSummary
+    {
+        /// <summary>
+        /// Gets or sets the connection server name
+        /// </summary>
+        public virtual string ServerName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the connection database name
+        /// </summary>
+        public virtual string DatabaseName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the connection user name
+        /// </summary>
+        public virtual string UserName { get; set; }
+    }
+}