opengl: port the shader to ColorPipeline
Instead of supplying color descriptions and having to manually ensure that the CPU/KMS
representations of the color pipeline match with the shader code, with this commit the
shader takes in a ColorPipeline and executes the operations in it.
The old headers colormanagement.glsl and saturation.glsl are kept for backwards compatibility,
at least until a good alternative solution for effects is provided.
Edited by Xaver Hugl