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.
The new producer does not have a synchronous mode (see the Javadoc for KafkaProducer#send: https://apache.googlesource.com/kafka/+/trunk/clients/src/main/java/org/apache/kafka/clients/producer/KafkaProducer.java), so I don't know what else I can test.

Regarding the ThreadPoolQueuedSink, it may be a good idea to keep the thread pool since any one thread may get blocked while waiting for the KafkaProducer.send() request to finish.  We'd want the ability to start sending another request simultaneously because the next message may be going to a different kafka broker, right?