MySQL query optimizations:
- During software ingestion, switched to updating last_opened_at as a batch (for 1 host).
- Removed DELETE FROM software statement that ran for every host update (when software was deleted). The cleanup of unused software is now only done during the vulnerability job.
- `/api/v1/fleet/software/versions/:id` endpoint can return software even if it has been recently deleted from all hosts. During hourly cleanup, this software item will be removed from the database.