update table listing and add callbacks

lib/Froxlor/UI/Callbacks/Text.php

@@ -0,0 +1,25 @@
+<?php
+namespace Froxlor\UI\Callbacks;
+
+/**
+ * This file is part of the Froxlor project.
+ * Copyright (c) 2010 the Froxlor Team (see authors).
+ *
+ * For the full copyright and license information, please view the COPYING
+ * file that was distributed with this source code. You can also view the
+ * COPYING file online at http://files.froxlor.org/misc/COPYING.txt
+ *
+ * @copyright  (c) the authors
+ * @author     Froxlor team <team@froxlor.org> (2010-)
+ * @author     Maurice Preuß <hello@envoyr.com>
+ * @license    GPLv2 http://files.froxlor.org/misc/COPYING.txt
+ * @package    Listing
+ *
+ */
+class Text
+{
+    public static function boolean(string $data): string
+    {
+        return $data ? '<i class="fa fa-check-circle"></i>' : '<i class="fa fa-times-circle"></i>';
+    }
+}