Normalize accounts that were closed manually

#2412 implemented account closing differently than the `deactivate` script that was being run manually before: we don't rename the participant by prefixing `deactivated-` anymore, and we clear personal information. This PR updates the DB to make it as if the deactivated accounts had been closed using the new method.
Is there a need to set so many things? It seems like all you'd want is:
```sql
UPDATE participants
   SET username = substring(username from 13)
     , username_lower = lower(substring(username from 13))
     , is_closed = true
 WHERE username LIKE 'deactivated-%';
```