Texture index (UV channel) as parameter in base material

Tex cord(0) could be a parameter to set in material instance as needed for each texture.

Now everyone use workaround with true/false to tex cord(0) and tex cord(1)

Example:
UV channel 0 - lightmap
UV channel 1 - Albedo
UV channel 2 - normal map
UV channel 3 - normal map for another part of a mesh

Material instance with ability to set for each of them 0 1 or 2nd index without workaround