Index Desktop Applications (#4422)

* Added support to index desktop app

* Fixed dedup for url files

* Added internet shortcut scheme for epic games

* Added test for internet shortcut dedup

* Updated hostname for steam game

src/modules/launcher/Plugins/Microsoft.Plugin.Program/Settings.cs

@@ -13,6 +13,8 @@ namespace Microsoft.Plugin.Program
 
         public bool EnableStartMenuSource { get; set; } = true;
 
+        public bool EnableDesktopSource { get; set; } = true;
+
         public bool EnableRegistrySource { get; set; } = true;
 
         internal const char SuffixSeparator = ';';