Add default configuration for Pulsar Grafana dashboards

[lhotari]

Motivation

Using Prometheus and Grafana in the Pulsar Helm chart isn't very useful without Pulsar dashboards.

Modifications

Add default configuration for Pulsar Grafana dashboards. The Grafana dashboards are referenced by URL from the ASL 2.0 licenced repo https://github.com/streamnative/apache-pulsar-grafana-dashboard which contains maintained Pulsar Grafana dashboards.

The changes in this PR will populate Grafana with the Pulsar dashboards:

Verifying this change

• Make sure that the change passes the CI checks.

[lhotari]

@Mortom123 @frankjkelly Do you have a chance to review this PR?

[frankjkelly]

Noticed a few small typos / formatting issues

[lhotari]

Noticed a few small typos / formatting issues

Thanks for the review @frankjkelly . I pushed changes to address your comments. PTAL

[frankjkelly]

LGTM

[dave2wave]

When deployed this way it is possible for a Grafana Admin to delete and redeploy any dashboard they wish? I ask because the StreamNative Pulsar Grafana Dicker image does a very strange deployment and build into the Grafana provisioning directories.

[lhotari]

When deployed this way it is possible for a Grafana Admin to delete and redeploy any dashboard they wish? I ask because the StreamNative Pulsar Grafana Dicker image does a very strange deployment and build into the Grafana provisioning directories.

There is no StreamNative Pulsar Grafana Docker image in play. Grafana's Helm chart is used under the covers and that has multiple ways to configure the Grafana dashboards. Documentation is at https://github.com/grafana/helm-charts/blob/main/charts/grafana/README.md#import-dashboards .