Provide some scriptage to port over entries from the old `skycomponents.db` DSO database to the new system

As I pointed out on Matrix, one of the issues in porting over to the old DSO database system is that some of our users (I'm an example) would have built up data on a lot of objects in their skycomponents.db databases, particularly in the _Manual_Additions and _Internet_Resolved catalogs which cannot be re-generated as easily.

Actually, the two MRs !369 (closed) and !366 (merged) provide hackish solutions to recover at least the _Internet_Resolved contents -- one can dump the list of objects with some care from the old catalog and ingest it in, but it would be much better served to have a script to port "out" the data from skycomponents.db. Feel free to assign it back to me if you're short on time.