Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the file
`.reuse/dep5`.
This commit also adds a Github workflow to check pull requests and adapts
copyright.pl to the changes.
Closes#8869
- bump actions/checkout from 2 to 3
- bump actions/upload-artifact from 1 to 3
- bump github/codeql-actions from 1 to 2
- use version tag for actions/checkout
Closes#8843