mod_muc_markers: replace configurable multi-marker tracking with better system Now tracks a single marker, but automatically applies rules from the XEP about "higher" markers implying "lower" markers - i.e. "displayed" implies "received". Still, just a single marker is tracked and synthesized at all times (the one configured with muc_marker_name).

local count_registering = module:measure("user_registering", "rate");
local count_registered = module:measure("user_registered", "rate");

module:hook("user-registering", function ()
	count_registering();
end);

module:hook("user-registered", function ()
	count_registered();
end);