feat(chart): add ServiceMonitor for controlplane metrics scraping

[synthe102]

Motivation

This change allows to create a ServiceMonitor resource instance used by prometheus operator and various telemetry collectors to scrape control plane metrics. While the prometheus.io/scrape Service annotation is used by some collectors, it seems that ServiceMonitors adoption is better.

Implementation information

Adds a new boolean controlPlane.serviceMonitor.enabled which default to false, controlling the templating of the ServiceMonitor.

Supporting documentation

[github-actions]

Reviewer Checklist

🔍 Each of these sections need to be checked by the reviewer of the PR 🔍:
If something doesn't apply please check the box and add a justification if the reason is non obvious.

• Is the PR title satisfactory? Is this part of a larger feature and should be grouped using > Changelog?
• PR description is clear and complete. It Links to relevant issue as well as docs and UI issues
• This will not break child repos: it doesn't hardcode values (.e.g "kumahq" as an image registry)
• IPv6 is taken into account (.e.g: no string concatenation of host port)
• Tests (Unit test, E2E tests, manual test on universal and k8s)
  • Don't forget ci/ labels to run additional/fewer tests
• Does this contain a change that needs to be notified to users? In this case, UPGRADE.md should be updated.
• Does it need to be backported according to the backporting policy? (this GH action will add "backport" label based on these file globs, if you want to prevent it from adding the "backport" label use no-backport-autolabel label)