Add ciflow_ruleset.json generator along with gha ci (#63097)
Summary:
- Add `.github/generated-ciflow-ruleset.json` for ciflow-bot (so that we can generate better comments)
- The lint job also checks git dirty to make sure that the file is always in sync with ciflow configs
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63097
Reviewed By: saketh-are
Differential Revision: D30263278
Pulled By: zhouzhuojie
fbshipit-source-id: bad68105a228e892ba071b29ecfdf433e1038054
