[package] implement `get_resource_reader` API (#51674)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51674
See
https://docs.python.org/3/library/importlib.html#importlib.abc.ResourceReader
Test Plan: Imported from OSS
Reviewed By: zdevito
Differential Revision: D26237034
Pulled By: suo
fbshipit-source-id: 4c19f6172d16b710737528d3de48372873b9368d
