[FEATURE REQUEST] Use built-in Prometheus exporter in HAProxy 2.2

[sk4zuzu]

Is your feature request related to a problem? Please describe.
We recently upgraded HAProxy in Epiphany. We still use old solution for exporting HAProxy metrics to Prometheus though... :'C

Describe the solution you'd like
BLOG POST: https://www.haproxy.com/blog/haproxy-exposes-a-prometheus-metrics-endpoint/

Our new HAProxy solution seems to have Prometheus plugin compiled-in https://github.com/docker-library/haproxy/blob/34f7b69c09fa0f16a0834641aa6556523c67b1ed/2.2/alpine/Dockerfile#L40 👍😇

How about migrating to compiled-in exporter? 🤔

Describe alternatives you've considered
We could do nothing!

Additional context
N/A

---

DoD checklist

• Changelog updated (if affected version was released)
• COMPONENTS.md updated / doesn't need to be updated
• Automated tests passed (QA pipelines)
  • apply
  • upgrade
• Case covered by automated test (if possible)
• Idempotency tested
• Documentation updated / doesn't need to be updated
• All conversations in PR resolved
• Backport tasks created / doesn't need to be backported

[rafzei]

It's well described in the blog post.

Ps. Now its time to stop do nothing

[przemyslavic]

Tested scenarios:
✔️ epicli apply -> epicli apply (x86_64 and aarch64)
✔️ epicli apply v1.0.1 -> epicli upgrade -> epicli upgrade (x86_64)
✔️ epicli apply v1.2.0 -> epicli upgrade -> epicli upgrade (aarch64)
✔️ Verified HAProxy metrics in Prometheus and Grafana.