Teach validate_drp about co-adds. This will be a full switch to coadd-based object definitions and forced photometry based on those defined objects.

1. Enable loading catalogs using the coadds
2. This should skip MultiMatch. Identify how to provide the same access capabilities to the calcsrd routines.
3. Add _coadd to default outputPrefix?
4. Decide on whether basing things on the coadd information, if available, will be the default option.