Add Harbor dashboard

[chess-knight]

Harbor exposes metrics using the Prometheus data model so we can easily start scraping Harbor instance’s metrics using Prometheus, see https://goharbor.io/docs/main/administration/metrics/.

For that purpose, we want to create also a dashboard, which will display Harbor metrics.

For inspiration, we can take the one from Harbor repository or find something else e.g. from Grafana dashboards.

[chess-knight]

Other interesting resources:

• https://sysdig.com/blog/monitor-harbor-registry/
• https://promcat.io/apps/harbor - includes dashboard and alerts

[chess-knight]

FYI: The grafana dashboard in the Harbor repository was updated, see https://github.com/goharbor/harbor/pull/16661.