examples, cloud-init: remove duplicated network data
examples, cloud-init: remove duplicated network data

Move this network data configuration to a const, and re-use it
when appropriate.

Signed-off-by: Miguel Duarte Barroso <c798d3f0e4fda7badfc3bbd91babde7ebd48b6c2@redhat.com>

kubevirt/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt