journal_data: Use datetime for origin-visit date field
This is preparatory work for !236 (closed)
Test Plan
tox is unhappy i've yet to understand why
Migrated from D3246 (view on Phabricator)
Staging instance, all changes can be removed at any time
This is preparatory work for !236 (closed)
tox is unhappy i've yet to understand why
Migrated from D3246 (view on Phabricator)