feat: user audit log

[cquintana92]

This PR performs the following changes:

• Extract the payment processor handling code from the server.py into smaller files.
• New migration that adds the new UserAuditLog entity
• Cron that removes the entries periodically after some time
• Remove the dry-run option from the cron and make the script not need to register the jobs twice (elif and choices)
• Add lots of user audit log emit events
• Some tests that check that the proper events are emitted (not all of the because there are too many)