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/Explorer/FindNodesRequest.cs

@@ -0,0 +1,55 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Collections.Generic;
+using Microsoft.SqlTools.Hosting.Contracts;
+using Microsoft.SqlTools.DataProtocol.Contracts.Connection;
+
+namespace Microsoft.SqlTools.DataProtocol.Contracts.Explorer
+{
+    /// <summary>
+    /// Information returned from a <see cref="FindNodesRequest"/>.
+    /// </summary>
+    public class FindNodesResponse
+    {
+        /// <summary>
+        /// Information describing the matching nodes in the tree
+        /// </summary>
+        public List<NodeInfo> Nodes { get; set; }
+    }
+
+    /// <summary>
+    /// Parameters to the <see cref="FindNodesRequest"/>.
+    /// </summary>
+    public class FindNodesParams
+    {
+        /// <summary>
+        /// The Id returned from a <see cref="CreateSessionRequest"/>. This
+        /// is used to disambiguate between different trees. 
+        /// </summary>
+        public string SessionId { get; set; }
+
+        public string Type { get; set; }
+
+        public string Schema { get; set; }
+
+        public string Name { get; set; }
+
+        public string Database { get; set; }
+
+        public List<string> ParentObjectNames { get; set; }
+
+    }
+
+    /// <summary>
+    /// TODO
+    /// </summary>
+    public class FindNodesRequest
+    {
+        public static readonly
+            RequestType<FindNodesParams, FindNodesResponse> Type =
+            RequestType<FindNodesParams, FindNodesResponse>.Create("explorer/findnodes");
+    }
+}