Question: Is `config/prometheus/cluster_metrics.yml` still used?
Description
While exploring our code, I found that the followinfg file used the old yml format for dashboards:
https://gitlab.com/gitlab-org/gitlab/blob/master/config/prometheus/cluster_metrics.yml#L1
It uses queries, appearance and required_metrics which AFAIK we are not supporting anymore.
Goal
If this file is marked for removal, I would like to also remove the support for appearance at the time series.