Update system to Debian 12 (Bookworm)

[jiru]

Tatoeba currently runs on Debian 11, which LTS will end soon (31 Aug 2026).

There are 3 systems to update:

• tatovm
• tatoeba.org
• dev.tatoeba.org

We need to make sure these components work:

• Horus (depends on python2)
• PHP 7.4 (needs external package)
• Manticore (old package!)
• Tatomecab
• Sinoparserd
• Tatodetect
• Tatowiki
• Jenkins (only for dev.tatoeba.org)
• Certbot
• Weekly exports