Python/C++ API Parity: Add impl and tests for ParameterDict (#40654)
Summary:
This diff contains the implementation of C++ api for ParameterDict from https://github.com/pytorch/pytorch/issues/25883, refer to https://github.com/pytorch/pytorch/issues/36904 and https://github.com/pytorch/pytorch/issues/28652
Pull Request resolved: https://github.com/pytorch/pytorch/pull/40654
Test Plan: Add unit test in this diff
Differential Revision: D22273265
Pulled By: glaringlee
fbshipit-source-id: 9134a92c95eacdd53d5b24470d5f7edbeb40a488
