db: Drop unused indexes on security_event_logs table
Created by: eseliger
These indexes seem to just be copied over from the event_logs table, where we actually use them. We don't require them here though and the cost is very high, these are in fact the heaviest indexes we have. Dropping these on will
- Give us faster inserts, so less impact by logging security events
- On dotcom, free 25351MB of disk space
- On dotcom, give us up to 25G back for other things to cache in memory, if postgres decided the indexes need to be in memory (which it probably did)