Avoid redundant copies for JP2 OBJs

If you ingest a JP2 as your Large Image OBJ, Islandora still creates a JP2 derivative datastream, which is a copy of the original OBJ. This essentially doubles the footprint of a JP2 Large Image object in your storage, unnecessarily since the JP2 and OBJ datastreams use the same file.

I don't know if this is technically possible, but it would be nice if the Large Image CModel could refer to the OBJ in the JP2 datastream, instead of making a separate copy of the same file. (Unless it already does this behind the scenes and I just don't know about it?)