vm-status: adapt for new grafana panels

[leona-ya]

This changes the panels of the vm-status dashboard for compatibility with future Grafana versions (the old ones are currently deprecated). It has almost no UI changes.
There's one intentional change: The left axis of the "Conntrack Table Fullness" Panel now has a scale 0-100%, so that it's a better visual indicator if there's a problem.

Current state

I tested this on my private grafana, but not on a FCIO one. ToDos:

• Test on FCIO instance, Also whether the remaining panels work
• Test for upgradeablity on customer instances
• Communicate the change of the Conntrack table graph(?) – when we decide to change this.

[ctheune]

I'm a bit lost here with the process. @zagy signaled that this is gnarly ... -_-

[zagy]

The export seems to have become better so that there is no hostname in there by default. Checking.

[zagy]

Hm … i can't get it imported, yet. So, later.

[leona-ya]

I already manipulated the export :/ The default is really dumb (e.g inlcudes hostname, data source identifier)