We don't need to support upgrades from 2 year old installs,
just from the last major version.
Also changed most retried tasks to 1s delay instead of longer.
ingress-nginx 0.16.2 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.16.2)
This patch simplify ingress-nginx deployment by default deploy on
master, with customizable options; on the other hand, remove the
additional Ansible group "kube-ingress" and its k8s node label
injection.
Reference to https://kubernetes.io/docs/concepts/services-networking/ingress/#prerequisites:
GCE/Google Kubernetes Engine deploys an ingress controller on the master.
By changing `ingress_nginx_nodeselector` plus custom k8s node
label, user could customize the DaemonSet deployment target.
If `ingress_nginx_nodeselector` is empty, will deploy DaemonSet on
every k8s node.
