Limit the number of prev_events of new events

Respect use_frozen_dicts option in workers

default config: blacklist more internal ips

Remove unused but buggy function

More updates to Promethese metrics exposition

Replace postgres GIN with GIST

This is because GIN can be slow to write too, especially when the table
gets large.

Don't error on non-ascii passwords

Set CORs headers on responses from the media repo

Remove sent_transactions table.

Update documentation about exported prometheus metrics

This should further reduce the number of individual inserts,
transactions and updates that are required for keeping sent_transactions
up to date.

Remove long-deprecated instructions about promethesus console; also fix for modern config file format

Bugfix for process-wide metric export on split processes