storage*: Drop obsolete fields from origin_visit
This removes:
- removes those columns from the backends (cass, pg)
- removes the status, metadata and snapshot from OriginVisit object instantiation
- creates the initial origin-visit-status status to "created" when adding a new origin-visit
Depends on journal (test data update D3344, code adaptation swh-journal!253 (closed)).
This also fixes the current failed build master [1]
Related to T2310
Test Plan
tox
Migrated from D3342 (view on Phabricator)