Issue #1987894 by ParisLiakos, vijaycs85: Convert user_logout() to a new style controller.

.../modules/user/lib/Drupal/user/Access/LoginStatusCheck.php

...lib/Drupal/user/Controller/UserAutocompleteController.php

...odules/user/lib/Drupal/user/Controller/UserController.php

core/modules/user/user.module

core/modules/user/user.pages.inc

core/modules/user/user.routing.yml

core/modules/user/user.services.yml