Merge pull request #11 from ansibl8s/replace_default_ipv4_by_var

roles/docker/tasks/configure.yml

roles/docker/tasks/install.yml

roles/kubernetes/common/tasks/gen_certs.yml

roles/kubernetes/master/templates/apiserver.j2

roles/kubernetes/master/templates/proxy.kubeconfig.j2

roles/kubernetes/node/templates/kubelet.kubeconfig.j2

roles/network_plugin/templates/calico/network-environment.j2