feat: Helm - Grafana Dashboard

[SchoolGuy]

Summary

This PR adds a Grafana dashboard that exposes the metrics that both the operator and the pushgateway are exposing.

This is related (but not fixing) #860

Checklist

For Code changes

• [ ] Categorize the PR by setting a good title and adding one of the labels: bug, enhancement, documentation, change, breaking, dependency as they show up in the changelog
• [ ] PR contains the label area:operator
• [ ] Link this PR to related issues
• [ ] I have not made any changes in the charts/ directory.

For Helm Chart changes

• [x] Categorize the PR by setting a good title and adding one of the labels: bug, enhancement, documentation, change, breaking, dependency as they show up in the changelog
• [x] PR contains the label area:chart
• [x] PR contains the chart label, e.g. chart:k8up
• [x] Variables are documented in the values.yaml using the format required by Helm-Docs.
• [ ] Chart Version bumped if immediate release after merging is planned
• [x] I have run make chart-docs
• [x] Link this PR to related code release or other issues.

[Kidswiss]

@SchoolGuy

Looks like helm is not happy with the template :/ It tries to interpret some grafana dashboard variables as helm variables. You probably have to add some sort of escaping to prevent that.