Add license header template for QtCreator

Can be set in Tools -> Options -> C++ -> File Naming

Author: m-kuhn

doc/qt_creator_license_template

@@ -0,0 +1,15 @@
+/***************************************************************************
+  %FILENAME% - %CLASS%
+
+ ---------------------
+ begin                : %DAY%.%MONTH%.%YEAR%
+ copyright            : (C) %YEAR% by %USER%
+ email                : [your-email-here]
+ ***************************************************************************
+ *                                                                         *
+ *   This program 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 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/