we've had this for ages, and since I started with the new scripts
directory under pkgs (and anticipated we'll write more), it seems like a
good idea to move that script there and have them all in one place.
Certainly better than having it as one extremely long string inside Nix.
this is a helper script to send emails to people who've not logged in
for a while (currently hard-coded to "since 2023-01-01"). It also sends
weekly reminders to admins giving the current number of unused accounts.
It is in $PATH for all normal users; for usage, invoke it with --help,
or just see the email it send to admin@.
