Forge stage server updates

[Claudio Bantaloukas]

The forge-stage server has been updated with apt dist-upgrade.
Additionally anubis has been updated to version 1.23.1 and forgejo to 
version 13.0.3.

Rather than keep a PR with all the changes against the main branch of 
the forge repository, I'm going to start pushing my changes to a stage 
branch on the forge/forge repository.

Hopefully this message won't go out in encoded fashion...

Cheers,
Claudio