[dsc] Updates to Grafana example dashboards

[Jerry Lundström]

Hi all,

I've updated the dashboard JSON files in dsc-datatool repository, these
example graphs should now display correct values.

  <https://github.com/DNS-OARC/dsc-datatool/pull/84>

Previous values was wrong, they were displaying a `field(value) mean()`
of all y axis and changing time resolution did not work.

All graphs that has PPS/QPS has been changed to `field(value) sum()
math( / ($__interval_ms / 1000) )` which should show correct values no
matter which time resolution you pick or how you zoom the graph.

If you find any problems with the graphs feel free to report them here,
on GitHub or to me directly.

Also, if you have dashboard/graph creations of your own that you want to
share then I'd be happy to add them to the repository and to our test site.

Cheers,
Jerry