[quant][graphmode][fx][refactor] Move patterns to separate files (#43891)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/43891
Test Plan: Imported from OSS
Reviewed By: vkuzo
Differential Revision: D23429759
fbshipit-source-id: f19add96beb7c8bac323ad78f74588ca1393040c
