[TODO] Collection API support

[syoyo]

https://docs.omniverse.nvidia.com/extensions/latest/ext_usd-collections.html

Supporting Collection API is a required step to fully support Material Binging

#40

• Implement Prim attributes for Collection API
• Implement utility functions such like Collection::Contains(prim)

[github-actions]

This issue is stale because it has been open for 30 days with no activity.

[github-actions]

This issue was closed because it has been inactive for 14 days since being marked as stale.