[Quant] Added 4 bit support for embedding quantized module (#69769)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69769
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
```
Imported from OSS
Reviewed By: jbschlosser
Differential Revision: D33152674
fbshipit-source-id: 73e63383cf60994ab34cc7b4eedd8f32a806cf7f
