Discuss whether it makes sense to parametrize gnomAD resource paths

[gtiao]

This would allow users to supply their own local paths of gnomAD resources to our standard Python library functions, rather than rely on the hard-coded cloud references (e.g., meta.ht()).

This would likely be a large effort to revise existing functions, but we could do this if we get several requests for this functionality.

See discussion here: https://discuss.hail.is/t/hail-utilities-for-gnomad-in-local-cluster/1790

[nawatts]

As a side effect of supporting multiple cloud providers, broadinstitute/gnomad_methods#265 also allows loading resources from arbitrary buckets / paths.