setup a grafana server somewhere

Prometheus on its own is nice, but the graphs are not that great. We should setup Grafana on top of that instead.

Grafana is a pain in the bottom to install in Debian: there are upstream packages, but they are a mess so my approach has been to use Docker so far.

I guess we can use the test server for this for now.

note there is a puppet module for grafana, which supports deploying both with the upstream debian package and docker: https://forge.puppet.com/puppet/grafana