[Zurich] moderation cron only checks 'unconfirmed'

see mysociety/FixMyStreet-Commercial#459 - "a report is moderated as
soon as its state has changed for the first time from Erfasst (en:
Submitted / db: unconfirmed) to any other state."

Thus we move 'confirmed' problems from the 1-day moderation SLA, to
a 5-day one, with $include_parent unset (e.g. as with 'planned' it
is with the DM, so doesn't need to be sent to the parent body also.)
Suppress 'once' warning
[Zurich] report is moderated on first status change

mysociety/FixMyStreet-Commercial#459 - we move "confirmed" to being
a moderated-but-not-complete state, and run the check for ->overdue
also on changing status from 'unconfirmed' (but only the first time,
so only if $extra->{moderated_overdue} isn't already set.
[Zurich] test moderated_overdue

- is set to 0 on state change within time-limit
- is set to 1 on state change after time-limit
- only marks overdue on first time
[Zurich] quash undef warning on date-check
[Zurich] log details for closed_overdue

see mysociety/FixMyStreet-Commercial#459 the new requirement is for
"Innerhalb von fübeitstagen abgeschlossen" - a report is dealt with
(abgeschlossen) as soon as the public state is Beantwortet (db: fixed -
council or closed) or Unsichtbar (en: Invisible, db: hidden).

Have added this as {closed_overdue} but have retained the logic for
{subdiv_overdue} logged in the %extra hash for now, in case it is
needed.

Note: as per Matthew "as with confirmed/in progress this should be 6 -
it's five days from moderation so is most simply just done as being six
since creation"
[Zurich] test /admin/stats

First test that this page is only available to superuser.

Then test that the moderated and fixed stats are doing something that
is (hopefully) the spec in mysociety/FixMyStreet-Commercial#459
[Zurich] test factor out cleanup() routine
[Zurich] move mech test into override_config stanza

This was causing previous test failures when config != Zurich, due
to expected logic not getting triggered.
remove action check on admin_log

to allow a wider range of action logging.
[Zurich] log admin changes

To allow us to infer additional stats changes requirements such
as in mysociety/FixMyStreet-Commercial#459 better in future.