fixed dashboards and added new var -- node-exporter v0.16.0+

[wguto]

This fixes the problems of not getting data points on the dashboards.
The reason for this is that the metrics were out of date. When updating the metrics you will also need a new variable.
It is all fixed in this PR.

[fauzan-n]

@wguto can you tell us how to install this plugin with your commited version?

I tried to change the Json Directly but it doesn't reload

[ddy86]

@x-fauzan-x

1. git clone https://github.com/wguto/kubernetes-app.git
2. delete the old grafana's kubernetes-app plugin dir or move out of the plugins dir, and then move the git dir to grafana's plugin.
   My grafana pod config is

"volumeMounts": [
          {
            "name": "nfs-kube-system",
            "mountPath": "/var/lib/grafana",
            "subPath": "grafana"
          }
]

so, the plugin dir is nfs/grafana/plugins
3. restart the grafana pod.

[discostur]

@Daiyoung doesn't work for me ... i have node exporter v0.18.0 deployed and the new dashboards with the fixes from your repo are still broken