Support deploying Kafka with KRaft instead of ZooKeeper for consensus building

[soenkeliebau]

In later versions Kafka supports running without ZooKeeper and provides its own KRaft consensus algorithm.

We should look into enabling the operator to deploy Kafka in this mode.

[sbernauer]

I just wanted to mention that according to https://www.confluent.io/blog/zookeeper-to-kraft-with-confluent-kubernetes/:

With Kafka 4.0 and Confluent Platform 8.0, Kafka will complete its journey to KRaft by removing the deprecated ZK mode,

So we need to tackle this at some point of time

[NickLarsenNZ]

I assume we want a CRD change to remove the Zookeeper ConfigMap reference.

There will be a CRD versioning discussion during the on-site about how to version CRDs (eg: how to choose from v1alpha2 vs v1beta1 vs v2alpha1).