Databases get full

[slifty]

After leaving the system on for a few months it has run quite smoothly BUT the scrape log database has gotten pretty big (around 9 GB!).

I want to check to see if we're over-logging, but beyond that I think we can probably rotate out historic scrape logs (database level logs, not logfile logs).

Short term I'm going to manually clear out the historic logs on prod and dev, but this issue is meant to capture the need to add a new worker that runs once a day to clear out certain logs before a certain (configurable) time.