Renamed `mutt2task` to `neomutt-2task`, and renamed `sync-mail` to
`neomutt-syncmail`.
Changed key maps accordingly. Also systemd service even though I don't
think I'll use it again.
I have not used (most) of these services in a long time. This makes the
unlinking more official. Also paves the way for setting up simple
runit-managed user services.