docs(various): rephrase volume performance from cluster nodes to pers…

[Langleu]

…itent volumes

Description

related to https://github.com/camunda/team-infrastructure-experience/issues/198

The change proposes a rephrasing concerning volume performances.
The docs are very fixated on cluster nodes for scaling Zeebe, which implicitly is true but what you scale is the pods and the nodes are scaled due to tains and tolerations.
That's probably where the focus stems from also for the volume performances, as Zeebe doesn't scale based on the cluster node volumes but from the attached persistent volumes.
If a customer tried scaling their cluster volumes, they would not notice any benefits since it's a different entity to what is attached to Zeebe that needs the performance change.

When should this change go live?

• This change is not yet live and should not be merged until {ADD_DATE} (apply hold label or convert to draft PR)?
• There is no urgency with this change.
• This change or page is part of a marketing blog, conference talk, or something else on a schedule.
• This functionality is already available but undocumented.
• This is a bug fix or security concern.

PR Checklist

• I have added changes to the relevant /versioned_docs directory, or they are not for an already released version.
• I have added changes to the main /docs directory (aka /next/), or they are not for future versions.
• My changes require an Engineering review, and I've assigned an engineering manager or tech lead as a reviewer, or my changes do not require an Engineering review.
• My changes require a technical writer review, and I've assigned @christinaausley as a reviewer, or my changes do not require a technical writer review.

[Langleu]

reached out to ask-zeebe for a review from the matter experts

[deepthidevaki]

Rephrasing "cluster nodes" to "persistent volumes" makes sense to me. 🚀

[Langleu]

Thanks everyone!