Improve Topdesk organisation

Currently topdesk mails get put in semi random places.
Ideally it would be in its own folder and form threads.

Where it would be put in place is here: https://gitlab.skynet.ie/compsoc1/skynet/nixos/-/blob/d64997991dd97b6f8aa766feb6100eb82f3b555f/applications/email.nix#L107