[Features]Kafka support rack awareness

[lancelot1989]

Kafka Partition‘s replicas supports rack awareness, likes below

broker.rack=rack1
replica.selector.class=org.apache.kafka.common.replica.RackAwareReplicaSelector

broker.rack is dynamic according which node the pod is scheduled on. But k8s's downward api still cannot support Node Label(kubernetes/kubernetes#40610).

So maybe kubeblocks can implement its own standard mechanism. apecloud/kubeblocks#8463

Once we can get Node Label inside Pod, we can generate properties in startup scripts.