usermanager: More consistent method behaviour, errors, and (pre-)events This commit refactors most of the exported usermanager methods substantially to ensure that all of them correctly check for the presence of the host and method they are calling and return consistent errors if either is incorrect or missing. It also unifies the event and logging code, so as a result there are more events being fired than before this commit (it also adds pre- events so that modules can block an action from going ahead). We don't have good test coverage of this API, but some manual testing suggests it seems to be working okay...

-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--


local allow_registration = module:get_option_boolean("allow_registration", false);

if allow_registration then
	module:depends("register_ibr");
	module:depends("watchregistrations");
end

module:depends("user_account_management");