Maintenance page when in upgrade state (#13551)

* Added functionality to show maintenance page and fixed issues with showing custom api controllers and 404 page, when umbraco had been in install or upgrade state

* Fixed Tests

* Fixed typo

* Fixed issue with login screen redirecting to website when in upgrade state, instead of backoffice

src/Umbraco.Web.Common/Controllers/RenderController.cs

@@ -16,6 +16,7 @@ namespace Umbraco.Cms.Web.Common.Controllers;
 /// </summary>
 [ModelBindingException]
 [PublishedRequestFilter]
+[MaintenanceModeActionFilter]
 public class RenderController : UmbracoPageController, IRenderController
 {
     private readonly ILogger<RenderController> _logger;