[kube-prometheus-stack] Add Support for Public Custom Dashboard Bootstrap

[dtamienER]

Is your feature request related to a problem ?

I want to create a public dashboard in Grafana that can be accessed without a login form, as part of the kube-prometheus-stack deployment. This is for team members to view a specific dashboard with metrics without requiring credentials. Navigating the UI manually to set this up every time isn't ideal, and I need this to be bootstrapped programmatically during deployment.

Currently, I need a custom dashboard to:

1. Be accessible at a separate subdomain (e.g., monitoring.owndomain) without requiring a password.
2. Allow public access to a single dashboard while securing the rest of Grafana at grafana.owndomain.
3. Be deployed directly from the Helm chart without manual intervention.

I'd handle monitoring.owndomain and grafana.owndomain with Traefik on my own.

Describe the solution you'd like.

A Helm chart option to:

1. Define a dashboard JSON directly in values.yaml, as a ConfigMap or in a file.
2. Enable public access (anonymous user role set to Viewer) for this specific dashboard, without affecting other dashboards.

Describe alternatives you've considered.

1. Deploying a second kube-prometheus-stack where login is disabled and this dashboard is the default home page. However, this introduces overhead and duplication.
2. Manually configuring Grafana after deployment.

Additional context.

A feature like this would simplify the use case of exposing dashboards to teams or stakeholders who do not require full access to Grafana.