[dper3] Create dper LearningRate low-level module (#44639)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44639
As title; this will unblock migration of several modules that need learning rate functionality.
Test Plan:
```
buck test //dper3/dper3/modules/low_level_modules/tests:learning_rate_test
```
Reviewed By: yf225
Differential Revision: D23681733
fbshipit-source-id: 1d98cb35bf6a4ff0718c9cb6abf22401980b523c
