Add support for fits cubes?

[zairving]

Instead of a directory of individual fits files for each image, users may wish to combine all images (possibly per camera) into a single fits cube. It would be convenient for such users if fits cubes were supported by opticam_new.Reducer(). Mimicking the current approach for data directories would probably be safest (i.e., option for a single fits cube presumed to contain all images for all three cameras, and options for individual cubes for each camera).