AWS cost attribution (2d/4): automate deployment of the grafana dashboard definitions

[consideRatio]

The naming 2x/n is meant to indicate it can be worked in parallell amongside other 2x/n issues.

For this specific issue, you'd use a placeholder .jsonnet file from jupyterhub/grafana-dashboards until the one developed in #4875 is done.

Technical context

We have a github workflow to deploy grafana dashboards already, but what we deploy are the standardized dashboards in jupyterhub/grafana-dashboards.

I think perhaps we should adjust the deployer command used in the existing github workflow to determine if we are a AWS based cluster, and if so, deploy the cost attribution dashboard as well after deploying the jupyterhub/grafana-dashboards.

Definition of done

• We have automation to deploy the cost attribution dashboard to all AWS clusters
• Documentation is updated to rely on the automation over manual steps
  Especially consider updates to docs written in AWS cost attribution (1/4): write documentation on how to deploy the system to another community #4873 as that was written before automation to deploy dashboards were around.