Add option in the writer to author light links through builtin schemas

Currently the writer authors light links in usd as arnold data,
e.g. :
`primvars:arnold:light_groups` .

But USD has its own way of defining this through builtins schemas UsdCollectionAPI. Unfortunately, it's less efficient to read the later ones, because the logic is different between arnold and usd (shape-centric VS light-centric).
So for now the writer is authoring the arnold data.
We could want to add an option in the writer to control that

Start by locating the writer entry point that authors light links and review its current Arnold-data output, including primvars:arnold:light_groups. Investigate how UsdCollectionAPI builtins schemas are represented in this project; done means a writer option controls the authoring mode and verifies the resulting USD data.

Written by the indexing model from the issue text.