Add swap_filesets.py

[will-moore]

Adds the swap_filesets.py script developed as part of the workflow at IDR/idr-metadata#652

e.g.

$ python swap_filesets.py Fileset:1 Fileset:2
$ python swap_filesets.py Image:1 Image:2 --report --dry-run

# gets the Fileset from first image in each Plate. Swaps all images in each Fileset
$ python swap_filesets.py Plate:1 Plate:2 --report --dry-run

# matches Plates by name
$ python swap_filesets.py Screen:1 Screen:2

This will also print an psql command that is needed to update the original Fileset:1 to reference the key file of Fileset:2 which is assumed to be NGFF data.

[will-moore]

As discussed today in IDR meeting: we may not want to delete the old Filesets as part of the NGFF conversion workflow. We can leave them "orphaned" with no Images as a record of the previous state of the server.
Could possibly use details.externalInfo as a way to store the previous Fileset ID on each Image.

[will-moore]

I found https://docs.openmicroscopy.org/omero-blitz/5.5.8/javadoc/omero/model/ExternalInfo.html on ExternalInfo but no idea what the fields mean or how to store an arbitrary number there. This is being used by Glencoe? cc @sbesson