PID namespace sharing is disabled only in Kubernetes 1.7.
Explicitily enabling it by default could help reduce unexpected
results when upgrading to or downgrading from 1.7.
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.
* 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
