Add jupyterhub-dashboards grafana charts to CD

[minrk]

@yuvipanda is working on re-usable jupyterhub grafana dashboards in https://github.com/jupyterhub/grafana-dashboards

I've deployed it a couple times by hand to test it out. You can check it out here.

Part of the point of this is to support versioned / always-up-to-date dashboards in CD workflows like ours. We would need to:

• issue an Admin grafana token (current Editor token is not sufficient) (it seems this must be done by hand across multiple deploys)
• install jsonnet in CD environment
• clone the jupyterhub-dashboards repo (possibly pinned commit for easier explicit bumps)
• run GRAFANA_TOKEN=... ./deploy.py dashboards https://grafana.domain

As another step, we could switch to a similar jsonnet setup for all our dashboards. This would make versioning/reconstructing all of our grafana changes much easier. On the other hand, it would also make tweaking/updating them more tedious since you have to go though a deploy to see changes, instead of tweaking via grafana UI.

[yuvipanda]

On the other hand, it would also make tweaking/updating them more tedious since you have to go though a deploy to see changes, instead of tweaking via grafana UI.

I make the changes on the dashboard to play with, and then copy paste it to my local setup. You can also make a copy of the dashboard and do the things.

[yuvipanda]

I was thinking we can instead have a sidecar for grafana that will render these dashboards to disk, and keep it up to date that way. This side-steps the need for the admin token, making the deploy process much easier.