headers: Update copyright notices

Add an SPDX identifier where it was missing.

Standardize adding "(c)" after "Copyright", and add a comma between the
years and the copyright holders.

Add the origin of the files for the source of the Zephyr app.
Additionally, split the copyright lines between the original copyright
and the modifications made to the file in this repository.

Exclude the .idl files of the actuation_msgs package from the QA checks
configuration. As documented in README.md, they do not contain copyright
notices.

Issue-Id: SCM-5893
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
Change-Id: Ifce005400457c2002526a77c76bec737b64225f8