Set correct kubelet cgroup-driver also for kubeadm deployments

This follows pull request #1677, adding the cgroup-driver
autodetection also for kubeadm way of deploying.

Info about this and the possibility to override is added to the docs.

roles/kubernetes/node/templates/kubelet.kubeadm.env.j2

@@ -26,6 +26,7 @@ KUBELET_HOSTNAME="--hostname-override={{ kube_override_hostname }}"
 --pod-infra-container-image={{ pod_infra_image_repo }}:{{ pod_infra_image_tag }} \
 --kube-reserved cpu={{ kubelet_cpu_limit }},memory={{ kubelet_memory_limit|regex_replace('Mi', 'M') }} \
 --node-status-update-frequency={{ kubelet_status_update_frequency }} \
+--cgroup-driver={{ kubelet_cgroup_driver|default(kubelet_cgroup_driver_detected) }} \
 {% endset %}
 
 {# DNS settings for kubelet #}