making import_module private and deprecating public method (#67990)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67990
Duplicate of the following PR which was merged by mistake without ghimport
https://github.com/pytorch/pytorch/pull/67914
cc albanD NicolasHug
Test Plan: Imported from OSS
Reviewed By: H-Huang
Differential Revision: D32247560
Pulled By: jdsgomes
fbshipit-source-id: 8ba5ba7d17fc3d0d2c377da467ea805822e21ec1
