mod_muc_moderation: Stamp XEP-0421 occupant-id for the acting moderator Gives clients some hint about which moderator it was who did the deed. The @by attribute does have the nick of the actor, but they could change their nickname at some point, which is what occupant-id solves. Ref #1816

module:hook("authentication-success", function (event)
	local session = event.session;
	local sasl_handler = session.sasl_handler;
	session.log("info", "Authenticated with %s", sasl_handler and sasl_handler.selected or "legacy auth");
end);