Refactor origin-revision layer
Removed archive parameter from RevisionEntry since is was no longer required.
Refactored OriginEntry to include info about visit date and snapshot.
Revisions reachable from an OriginEntry are now queried separately and returned in an iterable.
Also origin_add
function was updated accordingly, and CLI command now uses a CSVOriginIterator similar to that previously developed for revisions.
Updated tests as well to ensure nothing was broken during the refactoring.
Migrated from D5822 (view on Phabricator)