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.Hosting.v2/Utility/Extensions.cs

@@ -0,0 +1,100 @@
+//
+// 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.Collections.Generic;
+
+namespace Microsoft.SqlTools.Hosting.Utility
+{
+    public static class ObjectExtensions
+    {
+
+        public static IEnumerable<T> AsSingleItemEnumerable<T>(this T obj)
+        {
+            yield return obj;
+        }
+        
+        /// <summary>
+        /// Extension to evaluate an object's ToString() method in an exception safe way. This will
+        /// extension method will not throw.
+        /// </summary>
+        /// <param name="obj">The object on which to call ToString()</param>
+        /// <returns>The ToString() return value or a suitable error message is that throws.</returns>
+        public static string SafeToString(this object obj)
+        {
+            string str;
+
+            try
+            {
+                str = obj.ToString();
+            }
+            catch (Exception ex)
+            {
+                str = $"<Error converting poperty value to string - {ex.Message}>";
+            }
+
+            return str;
+        }
+
+        /// <summary>
+        /// Converts a boolean to a "1" or "0" string. Particularly helpful when sending telemetry
+        /// </summary>
+        public static string ToOneOrZeroString(this bool isTrue)
+        {
+            return isTrue ? "1" : "0";
+        }
+    }
+
+    public static class NullableExtensions
+    {
+        /// <summary>
+        /// Extension method to evaluate a bool? and determine if it has the value and is true.
+        /// This way we avoid throwing if the bool? doesn't have a value.
+        /// </summary>
+        /// <param name="obj">The <c>bool?</c> to process</param>
+        /// <returns>
+        /// <c>true</c> if <paramref name="obj"/> has a value and it is <c>true</c>
+        /// <c>false</c> otherwise.
+        /// </returns>
+        public static bool HasTrue(this bool? obj)
+        {
+            return obj.HasValue && obj.Value;
+        }
+    }
+
+    public static class ExceptionExtensions
+    {
+        /// <summary>
+        /// Returns true if the passed exception or any inner exception is an OperationCanceledException instance.
+        /// </summary>
+        public static bool IsOperationCanceledException(this Exception e)
+        {
+            Exception current = e;
+            while (current != null)
+            {
+                if (current is OperationCanceledException)
+                {
+                    return true;
+                }
+
+                current = current.InnerException;
+            }
+
+            return false;
+        }
+    }
+
+    public static class CollectionExtensions {
+
+        public static TValue GetValueOrSpecifiedDefault<TKey, TValue>(this IReadOnlyDictionary<TKey, TValue> map, TKey key) 
+        {
+            if (map != null && map.ContainsKey(key))
+            {
+                return map[key];
+            }
+            return default(TValue);
+        }
+    }
+}