Find a permanent solution for Stem, or refactor Onionprobe to use Arti

Description

Stem might need to be replaced at some point. Options

1. Use a fork, or keep using the official branch if it gets maintained again:
   • Find a permanent solution for stem (#19158) · Issues · tails / tails · GitLab.
   • Stem is currently unmaintained. Maybe Onionshare wants to step up and take care of it? · Issue #1634 · onionshare/onionshare.
2. Move to Arti as the new Tor implementation. This requires a major rewrite on Onionprobe. Options:
   • Rewrite Onionprobe in Rust.
   • Use a Python wrapper for Arti (tpo/core/arti!2446 (merged)).