feat: Periodically cleanup historical job runs

[evenicoulddoit]

Apologies if this has already been addressed, but I can't see any mention of it from the documentation or previous issues.

I'm wondering whether any thought has been made into automatically deleting old jobs after a given time duration. Someone may wish to do this either for compliance reasons (e.g. data stored in the steps contains PII which must be deleted after X days for GDPR), or simple to avoid endlessly growing the database.

Looking at the Job and Step run models, they don't appear to apply any indexes on the created at markers, so this doesn't appear to be something which could be done performantly?