Clean up RHEL RDO repo creation

Move the distro logic into the template and remove the when: statements
from the role plays.

Change-Id: Ibdaf1b5ba7978ef8d7e593f6114653184e8b0175
Move the group_by for product type into common group_by.yml

Cleans up some redundant code

Change-Id: I7a19224a01368992f7824fd3f1c1518f17aec5ab