Deploy add-on to detection node termination/preemption on GKE

[dfernandezm]

This will avoid downtime given there's enough pods in other nodes.

Need to deploy this DaemonSet https://github.com/GoogleCloudPlatform/k8s-node-termination-handler (it will move pods around)

https://cloud.google.com/compute/docs/instances/preemptible#preemption-process