Adds BundlingOptions for better bundling support and moves all logic to the bundler (don't manually process urls).

src/Umbraco.Web.BackOffice/Controllers/BackOfficeController.cs

@@ -220,8 +220,7 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
             var result = await _runtimeMinifier.GetScriptForLoadingBackOfficeAsync(
                 _globalSettings,
                 _hostingEnvironment,
-                _manifestParser,
-                Url);
+                _manifestParser);
 
             return new JavaScriptResult(result);
         }