Import the source code for Window Walker (#1177)

Import the codebase for Window Walker 

- Not loaded into the module list 
- Not added it to the installer list.

src/modules/windowwalker/app/Window Walker/App.xaml.cs

@@ -0,0 +1,15 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.  Code forked from Betsegaw Tadele's https://github.com/betsegaw/windowwalker/
+
+using System.Windows;
+
+namespace WindowWalker
+{
+    /// <summary>
+    /// Interaction logic for App.xaml
+    /// </summary>
+    public partial class App : Application
+    {
+    }
+}