Retrieve /etc/resolv.conf data (if available)
Add checkNameserverOverlaps and call it to
make sure there are no conflicts
Add utils.GetNameserversAsCIDR and tests
Read /etc/resolv.conf and pull out nameservers,
formatting them as a CIDR block ("1.2.3.4/32")
Upstream-commit: 3560c922b193e0f6b06c715a7b920f90a5990859
Component: engine