Use the kafkaadmin client to query the kafka state

[scanterog]

In order to prepare kafka-kit for zk-less kafka, we need to implement at least the following methods from zkhandler into kafkaadmin/client. This should query kafka directly rather than zk.

• GetAllBrokerMeta
• GetAllPartitionMeta
• GetPartitionMap
• GetPendingDeletion
• GetReassignments
• GetTopicConfig
• GetTopicState
• GetTopicStateISR
• GetTopics
• GetUnderReplicated
• UpdateKafkaConfig

[dekimsey]

Would this also include support for the commonly used --bootstrap-server argument used by the native Kafka clients to point to Kafka instead of Zookeeper?