[export] Add a data type for representing export workflow information. (#95013)
upstreaming some of our internal work to OSS so that we can get a better
preiew of how export pipeline works. there'll be more modularized work
sent in later.
Fixes #ISSUE_NUMBER
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95013
Approved by: https://github.com/tugsbayasgalan
