render/color: replace COLOR_TRANSFORM_LUT_3D with COLOR_TRANSFORM_LCMS2

Converting the LCMS2 transform to a 3D LUT early causes issues:

- It's a lossy process, the consumer will not be able to pick a
  3D LUT size on their own.
- It requires unnecessary conversions and allocations: an intermediate
  3D LUT is allocated, but the renderer already allocates one.
- It makes it harder to support arbitrary color transforms in the
  renderer, because each type needs to be handled differently.

Instead, expose a function to evaluate a color transform, and use
that to build the 3D LUT in the renderer.

include/render/vulkan.h

@@ -516,6 +516,7 @@ struct wlr_vk_color_transform {
 	struct wl_list link; // wlr_vk_renderer, list of all color transforms
 
 	struct {
+		size_t dim;
 		VkImage image;
 		VkImageView image_view;
 		VkDeviceMemory memory;