Change the unique constraint of the target table in targetdb

In the target database, I set the unique constraints on user-supplied targets by (proposal_id, ob_code), while the unique constraint defined in the datamodel is (catId, objId). I heard perhaps from Yabe-san that there were some issues in the previous engineering run because of the inconsistent definition of the unique constraint to make pfsDesign files. As mentioned in the obsproc channel in Slack, I'm going to assign catId for each proposal. Then, in general, proposal_id and catId are nearly equivalent, so I don't expect that conflicts happen again. However, I can also make the unique constraint as (obj_id, proposal_id, ob_code, catalog_id) to make sure to prevent the issue on the database level, and this would be a better option for the future.