In order to make things more and more asynchronus and to each time we
paint be an isolated event, that can be potentially be applied
individually or together with other updates, make it so that each time
we draw, we use the transient MetaFrameNative (ClutterFrame) instance to
carry a KMS update for us.
For this to work, we also need to restructure how we apply mode sets.
Previously we'd amend the same KMS update each frame during mode set,
then after the last CRTC was composited, we'd apply the update that
contained updates for all CRTC.
Now each CRTC has its own KMS update, and instead we put them in a per
device table, and whenever we finished painting, we'll merge the new
update into any existing one, and then finally once all CRTCs have been
composited, we'll apply an update that contains all the mode sets for all
relevant CRTCs on a device.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2855>
