Replace the current license disclaimer in files by
a SPDX-License-Identifier.
Task-number: QTBUG-67283
Change-Id: I708fd1f9f2b73d60f57cc3568646929117825813
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
It will become more complicated, so pull it into its own files.
Change-Id: If362f0775cc9d97a3c715c046d32d6a20c30a1f9
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>