mod_http_oauth2: Fire authentication events on login form For e.g. mod_audit_auth to use. A bit hacky because upon review many modules don't seem to handle the lack of an XMPP session in the event payload.

This module produces more detailed HTTP logs for Prosodys built-in HTTP
server. The format is similar to that of Apache and go into Prosodys
normal logs at the `info` level.