[cern] k8s: Use ClusterFirstWithHostNet with hostNetwork
upstream: https://review.opendev.org/c/openstack/magnum/+/780255
To not overload the cloud DNS, ClusterFirstWithHostNet is recommended when using hostNetwork.
story: 2008711 task: 42045
Change-Id: Ifc87980dd7e501dbd0fb1d457b3955f6fa34989b Signed-off-by: Spyros Trigazis spyridon.trigazis@cern.ch