Docs: Kafka capacity planning for ingest storage architecture

Is your documentation request related to a feature? If so, which one?

Ingest Storage Architecture

What is the solution that you would like or the expected outcome?

Latest Mimir documentation has vague information on how to do capacity planning on Kafka topic. It will be helpful to have it documented.

What did you think would happen?

At present we are evaluating the Kafka topic setup for production use so as per the present documentation we don't have any clue on how to decide on below things.

1. How many partitions should we have on the topic?
2. What is the ideal retention to set on Kafka topic?
3. Should the Kafka broker setup be a stretch cluster vs mirror maker one?
4. How to switch between Kafka sites if it has multiple sites. like Main vs DR sites.

What was your environment?

Present: POC with Mimir 3.0.1 on Centos 7/8/9 (for production) Deployment mode: manually through scripting.

Any additional context to share?

No response