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.CoreServices/LanguageServices/QueueItem.cs

@@ -0,0 +1,77 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Threading;
+
+namespace Microsoft.SqlTools.CoreServices.LanguageServices
+{
+    /// <summary>
+    /// Class that stores the state of a binding queue request item
+    /// </summary>    
+    public class QueueItem
+    {
+        /// <summary>
+        /// QueueItem constructor
+        /// </summary>
+        public QueueItem()
+        {
+            this.ItemProcessed = new ManualResetEvent(initialState: false);
+        }
+
+        /// <summary>
+        /// Gets or sets the queue item key
+        /// </summary>
+        public string Key { get; set; }
+
+        /// <summary>
+        /// Gets or sets the bind operation callback method
+        /// </summary>
+        public Func<IBindingContext, CancellationToken, object> BindOperation { get; set; }
+
+        /// <summary>
+        /// Gets or sets the timeout operation to call if the bind operation doesn't finish within timeout period
+        /// </summary>
+        public Func<IBindingContext, object> TimeoutOperation { get; set; }
+
+        /// <summary>
+        /// Gets or sets the operation to call if the bind operation encounters an unexpected exception.
+        /// Supports returning an object in case of the exception occurring since in some cases we need to be
+        /// tolerant of error cases and still return some value
+        /// </summary>
+        public Func<Exception, object> ErrorHandler { get; set; }
+
+        /// <summary>
+        /// Gets or sets an event to signal when this queue item has been processed
+        /// </summary>
+        public virtual ManualResetEvent ItemProcessed { get; set; } 
+
+        /// <summary>
+        /// Gets or sets the result of the queued task
+        /// </summary>
+        public object Result { get; set; }
+
+        /// <summary>
+        /// Gets or sets the binding operation timeout in milliseconds
+        /// </summary>
+        public int? BindingTimeout { get; set; }
+
+        /// <summary>
+        /// Gets or sets the timeout for how long to wait for the binding lock
+        /// </summary>
+        public int? WaitForLockTimeout { get; set; }
+
+        /// <summary>
+        /// Converts the result of the execution to type T
+        /// </summary>
+        public T GetResultAsT<T>() where T : class
+        {
+            //var task = this.ResultsTask;
+            return (this.Result != null)
+                ? this.Result as T
+                : null;
+        }
+    }
+}