Feature summary (what you would like to be able to do and where):
I'd like to be able to expire/delete old AbuseFilter log entries. These can take a significant amount of space in the database.
This could either be done automatically (automatically expire old entries older than a specific time) or a maintenance script.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
I've been using AbuseFilter to block spam for ca. 10 years now. Over that time, AbuseFilter has blocked 300'000 spam attempts (compared to 15'000 edits that were either legitimate or not caught by AbuseFilter). AbuseFilter seems to keep old entries forever, significantly increasing the database size. This makes e.g. backups harder.

I'd like to remove old entries to reduce database size.

Benefits (why should this be implemented?):

Would significantly reduce database size.
Has been requested by me (https://www.mediawiki.org/wiki/Topic:Xsx2tgyvxowpy7hr ) and by someone else (https://www.mediawiki.org/wiki/Extension_talk:AbuseFilter/Archive_1#c-Superxain-2013-01-28T12:25:00.000Z-How_can_I_remove_logs? )