Periodically sync for stale recordings

[NickM-27]

This PR accomplishes the following:

1. adds a schedule to run recordings sync once a week
2. previously only the DB was cleaned up, but now stale recordings files without a DB entry will also be cleaned up

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[blakeblackshear]

This is still likely to overwhelm many users setups.

A couple ideas to consider:

• Do it in batches. Maybe just check one day of recordings per loop.
• Slow it down intentionally with pause statements to create more space for other threads.
• Add a config option and make it disabled by default.
• Log warning messages and ask for users to report since this really shouldn't be happening.