converters: Write object_bytes and raw_manifest on revisions and releases
This allows representing all git objects instead of rejecting objects that do not fit in our "normal" data model.
This diff is restricted to revisions and releases for now, a future diff will add directories.
Depends on swh-model!312 (closed).
Test Plan
will fail until swh-model!312 (closed) is released.
Migrated from D6894 (view on Phabricator)