Improve reporting on autoban filter lists

[ChrisLovering]

These changes have been discussed within the mod team.

This PR changes autoban filter alerts to be sent to #filter-log instead of #mod-meta. This is with the aim to reduce the amount of spam in #mod-meta.

On top of that, this PR adds a new command to generate a report of all autoban filters added in the past 7 days. This report is also scheduled to be sent to #mod-meta once a week at 6pm UTC.

Screenshots

Empty state:

Small number:

Large number of filters:

[ChrisLovering]

Rebased onto main (hence the forcepush)