Make $_REQUEST processing independent of sub-calls

- Move HTTPInputData::process() into App::runFrontend()
- Pass $_REQUEST (including processed Input) to every Module method
- Delete $_POST parameters at Module post() calls because of $_REQUEST

src/Module/Notifications/Notification.php

@@ -42,7 +42,7 @@ class Notification extends BaseModule
 	 * @throws \ImagickException
 	 * @throws \Exception
 	 */
-	protected function post(array $request = [], array $post = [])
+	protected function post(array $request = [])
 	{
 		if (!local_user()) {
 			throw new HTTPException\UnauthorizedException(DI::l10n()->t('Permission denied.'));