[Documentation] Improve cluster sizing doc on control plane/metastore/janitor #5872
Description
In the cluster sizing doc page, we say "The Control Plane, Metastore and, Janitor are lightweight components. Each of these services requires 1 replica."
But we should explicitely say that:
- A cluster must have only one Control Plane
- A cluster can have one or several metastore pods for HA only if postgresql metastore is used.
- A cluster must have only one Janitor