Remove K8s and Helm manifests

What does this merge request do and why?

• Remove K8s manifests
• Remove Helm manifests
• Update deployments doc
• Remove monitoring in Makefile

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Merge request checklist

• Tests added for new functionality. If not, please raise an issue to follow up.
• Documentation added/updated, if needed.

Contributes to #337