Extend PSF photometry to simultaneous fitting of multiple images, similar to the extract_stars framework?

[Onoddil]

Pretty lofty goal, but it seems we're not taking full advantage of the EPSFStar vs LinkedEPSFStar framework only allowing for fitting of a single image to sources at once. With constrain_centers on linked sources, it feels like it should be possible to allow for multiple images to be fit (in parallel or in series), with common knowledge of position of all sources being used to better constrain fluxes...

Fairly big extension, but just a thought I had... Is there a tag for "would be nice down the line" or something? Or a "lofty dream" tag?

[keflavich]

This is like DAOPHOT ALLFRAME, right?

I think this is a good idea. It's probably not cheap to implement.