feat(argo-cd): Add optional grafana dashboard (#2725)

[jcpunk]

Checklist:

• I have bumped the chart version according to versioning
• I have updated the documentation according to documentation
• I have updated the chart changelog with all the changes that come with this pull request according to changelog.
• Any new values are backwards compatible and/or have sensible default.
• I have signed off all my commits as required by DCO.
• I have created a separate pull request for each chart according to pull requests
• My build is green (troubleshooting builds).

This PR should permit folks to optionally install the example grafana dashboard in a way that the grafana sidecar can detect.

[tico24]

Can you please point me in the direction of where I can find this in the upstream release manifests?

Unsurprisingly I am extremely not keen on a 5000 line commit.

[jcpunk]

https://github.com/grafana-community/helm-charts/tree/main/charts/grafana#sidecar-for-dashboards explains how grafana's dashboard sidecar can automatically import dashboards.

[tico24]

I know how grafana's sidecar can do that but this isn't something contained within argocd's official release.

[jcpunk]

I pulled the dashboard in from : https://github.com/argoproj/argo-cd/blob/master/examples/dashboard.json

[tico24]

I know. That's also not the official release manifest.

[jcpunk]

Is this chart's policy to only include items from the tagged release manifest - excluding any items from the source tree which are not part of the explicitly provided items?

[mbevc1]

As stated in the README as official Helm Chart we only support released upstream versions:

Our official support is limited to the latest version of the upstream projects only.

[jcpunk]

I tend to view the content of the repo as part of the upstream release at the tagged commit - https://github.com/argoproj/argo-cd/archive/refs/tags/v3.4.3.tar.gz contains the dashboard.json file. I guess this is a difference of philosophy.

The dashboard is referenced directly at:

• https://argo-cd.readthedocs.io/en/stable/operator-manual/notifications/monitoring
• https://argo-cd.readthedocs.io/en/stable/operator-manual/metrics/#dashboards
• https://github.com/argoproj/argoproj-deployments/tree/master/prometheus-operator
  which feels at least semi-official.

Argo-cd itself has no runtime changes with this applied.

If you don't feel that this config map appropriate, I can close out this PR. I was just trying to make a smooth path for rendering the existing prometheus monitors within the chart.