Find a new home for the team mailing list

"Migration plans for lists.alioth.debian.org" https://lists.debian.org/debian-devel-announce/2018/01/msg00003.html

TODO:

• Request the debian-xen ML (done: https://bugs.debian.org/910673)
• Ask Alexander Wirt for instructions on how to move to a new ML
• Ask @iwj for an encrypted list of subscribers
• Ask @iwj for the archive of the old ML
• Ask @iwj for access to the new list if you don't have it yet
• Explore the ML interface to figure out what to do where
• Ensure that the archive is set up with monthly list and that is uses month numbers, not month names (like June)
• Import the old archive into the new ML
• Import the list of subscribers into the new ML
• ... ?