kubeadm support (#1631)

* kubeadm support

* move k8s master to a subtask
* disable k8s secrets when using kubeadm
* fix etcd cert serial var
* move simple auth users to master role
* make a kubeadm-specific env file for kubelet
* add non-ha CI job

* change ci boolean vars to json format

* fixup

* Update create-gce.yml

* Update create-gce.yml

* Update create-gce.yml

roles/kubernetes/master/templates/known_users.csv.j2

@@ -0,0 +1,4 @@
+{% for user in kube_users %}
+{{kube_users[user].pass}},{{user}},{{kube_users[user].role}}{% if kube_users[user].groups is defined %},{% set groups_csv = kube_users[user].groups|join(',') -%}"{{groups_csv}}"{% endif %}
+
+{% endfor %}