[sparsity] Sparsity parametrization (#58705)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/58705
The basic demo for this particular implementation can be found here:
https://gist.github.com/z-a-f/1d06ae8d5a509d3c9c1596dcb924afe0
Test Plan:
```
python test/test_ao_sparsity.py
```
Imported from OSS
Differential Revision:
D28970959
D28970959
Reviewed By: raghuramank100
Pulled By: z-a-f
fbshipit-source-id: 2a0bea1e0a81816690e05f83051d607c90925d32
