Deploy the latest version of swh.model and swh.storage to production.
- [x] make sure all new packages are available (swh.model, swh.storage, swh.deposit)
- [x] run the first half of the database migration, adding the new fields to both databases (somerset then belvedere)
- [x] check that postgresql replication still runs properly
- [x] stop all workers
- [ ] upgrade and restart gunicorn-swh-storage instances (saam, moma, webapp1, storage01.euwest.azure)
- [ ] upgrade and restart worker08
- [ ] check that new revisions and releases are getting the new offset fields populated
- [ ] restart all other workers
- [ ] run the data migration for the new fields on old objects
- [ ] add database constraints for all objects once the migration has run