migrate tails mailing lists to TPA infra

excerpt from the roadmap:

• Summary: Public mailing listsm, hosted at autistici/inventati.
  • amnesia-news@boum.org
  • tails-dev@boum.org
  • tails-testers@boum.org
  • tails-l10n@boum.org
• Interest-holders: Tails Team, Community Team
• Action: Merge
  • Migrate away from the boum.org domain
  • Merge into Tor's Mailman 3
• Complexity: Medium
• Constraints: ∅
• References:
  • https://tails.net/about/contact/index.en.html#public-mailing-lists

consider delegating to the tails team.