ClutterColorState, that is a GObject. each ClutterActor would own
such an object, and it'd be set via a GObject property.
It would have an API to get the colorspace, whether the actor
content is in pq or not, and things like that.
if it is NULL, it will default to color state with sRGB colorspace.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2443>
