Add python3 file for hardened images
Add python3 file for hardened images

Add a python3 file to support RHEL 8 for hardened images.  In addition
remove the screen package as its no longer supported.

Change-Id: I953c5648ac79dc8a59fd4bc798c21e6e383e1afc

openstack/tripleo-common,openstack/tripleo-common