v2.3.0 Red Hat Image support

Support for using Red Hat based images with DUE

The prior release had DUE able to run Debian based images on a Red Hat system.

This release supports creating DUE containers from Red Hat images, so that the user
can retain their identity in the container. So far it has only been tested with the 'example'
template, and support for this should be considered 'alpha' as it 'works fine for me' but
your mileage may vary.

sha1sum of the due deb below is
fcfa6e04a785ee5246da102dd2e36b00965598f3 ../due_2.3.0-1_all.deb