Follow-up to #239, pairing with the CNPG VMPodScrape (#242). Imports the **CloudNativePG** dashboard (grafana.com 20417) as a `GrafanaDashboard` (gzipJson, datasources resolved to the in-cluster VictoriaMetrics uid). Now that #242 collects the postgres metrics, this dashboard renders real data for all CNPG clusters.
Reviewed-on: #243
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>
