[H5] Add support for exporting multiple UV channels and vertex colours for RMF format on Halo 5 models

[TacoHombre]

Currently Halo 5 scenarios don't export with multiple UVs or vertex colours which are used extensively in their maps, would love to see this implemented so proper ports can finally be made

[Gravemind2401]

The multiple UV channels should already be working for models that have it. Vertex colors shouldn't be too far off now.