Move $strings from App to Core\L10n

- Add L10n::init() call in App constructor
- Improve pushLang/popLang
- Remove no longer needed references to App

bin/worker.php

@@ -7,7 +7,6 @@
 use Friendica\App;
 use Friendica\Core\Config;
 use Friendica\Core\Worker;
-use Friendica\Core\L10n;
 
 // Get options
 $shortopts = 'sn';
@@ -30,9 +29,6 @@ require_once "boot.php";
 
 $a = new App(dirname(__DIR__));
 
-$lang = L10n::getBrowserLanguage();
-L10n::loadTranslationTable($lang);
-
 // Check the database structure and possibly fixes it
 check_db(true);