Refactoring SPDX check

[erikbosch]

Make sure that defined licenses are forwarded as arguments.
Increase scope of what is considered as comments
(Do not only check one-line comments)
Make sure to support comma separated list of comments

Example output checking for Apache or MIT

Prepare all required actions
Run ./.github/actions/spdx
Run $GITHUB_ACTION_PATH//verify-spdx-headers
2 will be accepted!
Allowed license: Apache-2.0
Allowed license: MIT
OK: Apache-2.0       /home/runner/work/kuksa.val/kuksa.val/kuksa-val-server/src/main.cpp
NO SPDX /home/runner/work/kuksa.val/kuksa.val/kuksa-val-server/test/unit-test/KuksavalUnitTest.cpp
OK: Apache-2.0       /home/runner/work/kuksa.val/kuksa.val/kuksa-val-server/test/unit-test/VssDatabaseTests.cpp
OK: Apache-2.0       /home/runner/work/kuksa.val/kuksa.val/kuksa_databroker/integration_test/test_databroker.py
OK: Apache-2.0       /home/runner/work/kuksa.val/kuksa.val/test/stresstest/broker.py
Traceback (most recent call last):
  File "/home/runner/work/kuksa.val/kuksa.val/./.github/actions/spdx//verify-spdx-headers", line 146, in <module>
    raise Exception("Check the output, some files have not the right licenses!")
Exception: Check the output, some files have not the right licenses!
Error: Process completed with exit code 1.

[lukasmittag]

Other than my small comment fine. Thanks for the effort!

[lukasmittag]

Looks good!