OpenUSD is outputting to terminal

[mwestphal]

Describe the bug
OpenUSD, the library used to read .usd is outputting to terminal a lot, even when reading file sucessfully, even when using --quiet

To Reproduce
Steps to reproduce the behavior:

1. Open the file using f3d --dry-run McUsd.usdz

Warning: in BindingsAtPrim at line 705 of /__w/f3d-superbuild/f3d-superbuild/build/superbuild/openusd/src/pxr/usd/usdShade/materialBindingAPI.cpp -- Found material bindings on prim at path (/McUsd/grass_block_top) but MaterialBindingAPI is not applied on the prim
Warning: in BindingsAtPrim at line 705 of /__w/f3d-superbuild/f3d-superbuild/build/superbuild/openusd/src/pxr/usd/usdShade/materialBindingAPI.cpp -- Found material bindings on prim at path (/McUsd/dirt) but MaterialBindingAPI is not applied on the prim
Warning: in BindingsAtPrim at line 705 of /__w/f3d-superbuild/f3d-superbuild/build/superbuild/openusd/src/pxr/usd/usdShade/materialBindingAPI.cpp -- Found material bindings on prim at path (/McUsd/grass_block_side) but MaterialBindingAPI is not applied on the prim
Warning: in BindingsAtPrim at line 705 of /__w/f3d-superbuild/f3d-superbuild/build/superbuild/openusd/src/pxr/usd/usdShade/materialBindingAPI.cpp -- Found material bindings on prim at path (/McUsd/iron_block) but MaterialBindingAPI is not applied on the prim
Warning: in BindingsAtPrim at line 705 of /__w/f3d-superbuild/f3d-superbuild/build/superbuild/openusd/src/pxr/usd/usdShade/materialBindingAPI.cpp -- Found material bindings on prim at path (/McUsd/gold_block) but MaterialBindingAPI is not applied on the prim
[...]

Expected behavior
No output to terminal that is not controlled by F3D, in the case of --quiet, there should be none.

Additional context
I understand that this output can be useful when debugging and we may want to have a way to keep it on when using --verbose, but it is more important to be able to turn it off.

Check for a flag in USD to turn that off, if not, patch it out.