Automatic tagging

As agreed in teleconferences, we still need to automate the creation of version tags. Still as discussed we need:
- Nightly tagging
- A way of triggering tagging manually

This probably should be implemented using Github Actions.

Start by reviewing the repository's GitHub Actions configuration and the current version-tagging process. Determine the workflow entry points needed for nightly tagging and manual triggering, then verify that both paths create the expected version tags.

Written by the indexing model from the issue text.