[TASK] Add copyright notice

Classes/Preview/PreviewService.php

 <?php
 
+/***************************************************************
+ *  Copyright notice
+ *  (c) sgalinski Internet Services (https://www.sgalinski.de)
+ *  All rights reserved
+ *  This script is part of the TYPO3 project. The TYPO3 project is
+ *  free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *  The GNU General Public License can be found at
+ *  http://www.gnu.org/copyleft/gpl.html.
+ *  This script is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *  This copyright notice MUST APPEAR in all copies of the script!
+ ***************************************************************/
 namespace SGalinski\SgNews\Preview;
 
 use TYPO3\CMS\Backend\Utility\BackendUtility;