added KafkaV2 sink using new kafka producer in 0.8.2-SNAPSHOT

@metacret here is the pull request that we discussed.  Please see suro-server/conf/sink_using_kafkaV2.json for the configuration syntax.
There is ProducerRecord constructor with key argument. SuroKeyedMessage is for semantic partitioning and if you discard the key information, semantic partitioning logic will be broken.