TODO:

• Remove from PyPI
• Remove from Docker Hub
• Remove from readthedocs
• Downgrade API worker
• Adjust changelog on main with explanation why 2.0.0 was yanked
• Remove spec v3.1
• Reset submodule in fsfe-website to pre-3.1 commit
• More, probably

This should all be done within the following 24h, with priority to remove from PyPI and Docker Hub.

See #773