mod_http_oauth2: Use new mod_cron API for periodic cleanup Less frequent but this isn't that important after all since, as the comment states, expired codes are not usable anyway. They're also not that large so memory usage probably doesn't matter.

This module discards typing notifications sent to a bare host JID,
preventing error replies to be sent. These errors are harmless but can
be annoying sometimes if your client shows them prominently.