Util is a bad name and static is awkward

Signed-off-by: Joas Schilling <coding@schilljs.com>

appinfo/app.php

@@ -35,7 +35,7 @@
 
 $manager = \OC::$server->getNotificationManager();
 $manager->registerNotifier(function() {
-	return \OC::$server->query('OCA\Spreed\Notification\Notifier');
+	return \OC::$server->query(\OCA\Spreed\Notification\Notifier::class);
 }, function() {
 	$l = \OC::$server->getL10N('spreed');
 
@@ -46,5 +46,6 @@ $manager->registerNotifier(function() {
 });
 
 \OC::$server->getUserManager()->listen('\OC\User', 'postDelete', function ($user) {
-	\OCA\Spreed\Util::deleteUser($user);
+	$listener = \OC::$server->query(\OCA\Spreed\HookListener::class);
+	$listener->deleteUser($user);
 });

lib/HookListener.php

@@ -23,15 +23,23 @@ namespace OCA\Spreed;
 
 use OCP\IUser;
 
-class Util {
+class HookListener {
+
+	/** @var Manager */
+	protected $manager;
+
+	/**
+	 * @param Manager $manager
+	 */
+	public function __construct(Manager $manager) {
+		$this->manager = $manager;
+	}
 
 	/**
 	 * @param IUser $user
 	 */
-	public static function deleteUser(IUser $user) {
-		/** @var Manager $manager */
-		$manager = \OC::$server->query(Manager::class);
-		$rooms = $manager->getRoomsForParticipant($user->getUID());
+	public function deleteUser(IUser $user) {
+		$rooms = $this->manager->getRoomsForParticipant($user->getUID());
 
 		foreach ($rooms as $room) {
 			if ($room->getType() === Room::ONE_TO_ONE_CALL || $room->getNumberOfParticipants() === 1) {