Those of us who aren't DAM would like to be able to use the RT
templates available from the site, such as for requesting the
addition of new DMs. Alter the template to talk about Front Desk
for DMs, and DAM for everything else.

(Potential future change: Also Front Desk for guest accounts.)

This reverts commit 9c4cb4b7.

keyring-maint have stopped building removed-keys.gpg, instead relying on
git history to record the existence of these no longer trusted keys.
Stop using this keyring to discover DDs that have been removed.

When a RM `retires' they should move back to contributor status; there
is no equivalent of emeritus for them. Add support for this rather than
treating DM removal as something that doesn't happen.

The checks in /wizard/process for the desired target status did not
gracefully handle an invalid destination (in particular dd is not valid,
it is dd_u). Fail with an invalid error message rather than a Python
backtrace.

Commit 751efb1b remove the use of naive
datetime in the latest stats page, but changed the resulting type from
a date to a datetime. Convert it back, avoiding a comparison error in
this page.

Recent refactoring lost a check to ensure we had an authenticated
visitor before checking if they were an admin. Add a check to see
if we have a user at all, and if not then correctly treat as not
being an admin.