[HybridPro] Support for material faces

[Derpius]

I have a large static mesh made up of a number of submaterials which I'm attempting to apply using rpr::Shape::SetMaterialFaces. This throws RPR_ERROR_UNSUPPORTED when using the HybridPro backend.

I can work around this by splitting the mesh by material into separate shapes at runtime, but material faces seem like the best way to do this (and makes the code a lot cleaner).