Issue 3291799: Sent logout routing to the route subscriber

Closes #3291799

• Added the route subscriber to the services.yml file.
• Removed the override for the user/logout route in the routing.yml file.
• Added the requirements and options from the old route to the route override in the route subscriber
• Did not include the title setting from the old route (this was suggested to not include in the issue description).

src/Routing/RouteSubscriber.php

@@ -19,6 +19,9 @@ class RouteSubscriber extends RouteSubscriberBase {
     // Reroute the default user.logout route.
     if ($route = $collection->get('user.logout')) {
       $route->setDefault('_controller', '\Drupal\openid_connect\Controller\OpenIDConnectRedirectController::redirectLogout');
+      $route->setRequirement('_user_is_logged_in', TRUE);
+      $route->setRequirement('_csrf_token', TRUE);
+      $route->setOption('no_cache', TRUE);
     }
   }