update draft json field to store list of resource IDs

[keithmanville]

DraftResource stores a base_resource_id and resource_id in the JSON payload column. This allows for a single subcollection. The field should be updated to instead store a list of resource_ids allowing for multiple nesting. This follows the pattern implemented in the python client.

Definition of done

• The fields in the JSON payload are updated
• An alembic migration script with upgrade and downgrade functions is implemented
• All tests pass
• The feature is merged into dev