Rainbow Zu

I've been calling this variant the "big gay zu" ever since Eureka and since it's back in South Horn as both a mob a FATE boss I felt inspired to make a mount recolor to steal his plumage.

Affects the Zu mount only, Bennu and Mountain Zu are unaffected despite showing in the file list.

Shoutout to raptorwastaken on xma for their super old pre-DT mod which I discovered way too late after making this (oops). We carry the rainbow torch forward.