Texture paths can't be correctly resolved for nested USDZ files

[hybridherbst]

Texture paths currently can't be resolved correctly for nested USDZ files. One level is fine.
Fixing this would require adjustments to the WASM bindings.

The current approach is very brute force: when texture references can't be found in the toplevel folder or file, the virtual filesystem is queried for all other potential toplevel files/USDZ archives to check if they are the one containing the texture.

That means that identical texture paths between different USDZ files most likely won't be resolved correctly.
Deeply nested USDZ files (USDZ inside USDZ) also will probably not work right now.

[beersandrew]

@hybridherbst i think this can be closed