[quant][graphmode] Refactor fusion to use the new Pattern format (#68770)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68770
Previous fusion only works for a sequnce of ops, which is not general enough for fusion patterns
that is defined by a subgraph, this PR refactors that to make it more general
Test Plan:
```
python test/test_quantization.py TestFuseFx
```
Imported from OSS
Reviewed By: vkuzo
Differential Revision: D32602637
fbshipit-source-id: a7897c62081b9d71c67fb56e78484cf68deaacf6
