Fix CLI chgrp for filesets with one object

See https://trac.openmicroscopy.org.uk/ome/ticket/11966

The graph commands are now wrapped in a `DoAll` so that the following should now work again:
```
bin/omero import test.fake
bin/omero chgrp my_grp /Image:id
```
Additionally check the new integration test pass.

An integration test has been added and marked as `xfail` to reflect the current incapacity of the CLI to run chgrp on multiple objects in one transaction, e.g.
```
bin/omero chgrp my_grp /Image:id1 /Image:id2
```
Arguably the latter could be addressed as part of this PR by wrapping all requests in a single DoAll call.  But this could be added as a ticket to 5.0.1 or 5.1.0.