Toast-style global notification state (#13341)

* toast style notification init

* Notificatino styles and messaging for variable save

* pre-PR cleanup

* Typo fix and 5sec timeout

* Prevent text from overlapping the close button

ui/app/controllers/application.js

@@ -15,6 +15,7 @@ export default class ApplicationController extends Controller {
   @service config;
   @service system;
   @service token;
+  @service flashMessages;
 
   queryParams = [
     {