R1:5e7a0917372a

Write an explicit edge for commit membership in packages

Summary:
Ref T10978. Currently, during commit import, we write an "Audit Not Required" auditor for commits which don't require an audit.

This auditor is used to power the "Commits in this package" query in Owners.

This conflates audits and commit/package membership. I think it might even predate edges. Code needs to dance around this mess and we get the wrong result in some cases, since auditors are now editable.

Instead, write an explicit edge…