Make create_transform_snippet method more consistent.
Abstract TransferFunction struct: convert it to ColorOpSnippet.
This transform snippet will be defined by these ColorOpSnippets.
These ColorOpSnippets are similar to the prescriptive DRM API for
color transformation.
A standard transform snippet would have as ColorOpSnippets:
1. eotf
2. luminance_mapping
3. color_space_mapping
4. inv_eotf
Update uniforms the same way the transform snippet is defined.
Update color transform key to consider how the transform snippet is
generated.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4144>
0095e7d50a