Describe your PR, what does it fix/add?

Support wp color-management. #9443
Added debug:full_cm_proto to switch proto into debug mode (requires restart).

In regular mode this implementation does almost nothing. It handles the minimum required subset of features.
In debug mode all features and values are marked as supported. Features related to fullscreen HDR will work the same as with xx-cm and frog-cm. Other features will only store and pass values and output some log messages.

Is there anything you want to mention? (unchecked code, possible bugs, found problems, breaking compatibility, etc.)

Needs #9064 to be useful. Without it xx-cm and frog-cm should be used instead because those protos are less likely to break things for newer clients with correct wp-cm support.
Needs nix wp version bump.
Needs a proper way of handling images description ids to avoid duplication (not a priority, very unlikely conditions to be useful)

Is it ready for merging, or does it need work?

Ready.

• use xml from wayland-protocols (requires wp 1.41)
• move bits from xx-cm and frog-cm to wp
• use internal enums
• add some common CM constants
• correctly state supported features
• add debug mode with all the features
• handle cm attached to subsurfaces