[Quant][improvement] Added 4 bit support for embedding quantized module (reland PR 69769) (#72276)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/72276
Added 4 bit support and the correpsonding test in the module api. Restructured the test_quantized_module for both 4 & 8 bit support.
Test Plan:
In pytorch main dir, execute
```
python test/test_quantization.py TestStaticQuantizedModule.test_embedding_api
```
Reviewed By: dagitses
Differential Revision: D33994544
Pulled By: dzdang
fbshipit-source-id: 49f04f267913e9f3f9649305b233055157c82dee
(cherry picked from commit c8c8e6fb449ab9a6432f881d069c1f05ab052332)
