docker-images(grafana): grafana v7

Created by: bobheadxi

Poked around and noticed that Grafana 7 doesn't have any major changes in any file formats :) https://grafana.com/docs/grafana/latest/installation/upgrading/#upgrading-to-v7-0

The UI is much improved and seems a lot nicer overall. It also comes with Jaeger support out of the box, which I've enabled for dev:

It seems like all the dashboards etc are working as expected

Unfortunately, for docs links Grafana only provides a URL for latest and not v7.0