Add variations on basic test cases, to investigate replication

[solsson]

Probably no merge, as this is for learning and for troubleshooting #116 and #132.

The "3acks" test is to try to exemplify producer behavior when insufficient acks are received. If kafka is scaled from 3 to 2, the original "produce-consume" test (#79) stays ready while the new "produce-consume-3acks goes Unready.

org.apache.kafka.common.errors.NotEnoughReplicasException: Messages are rejected since there are fewer in-sync replicas than required.
[2018-01-22 19:46:08,562] WARN [Producer clientId=console-producer] Got error produce response with correlation id 369 on topic-partition test-produce-consume-3acks-0, retrying (2 attempts left). Error: NOT_ENOUGH_REPLICAS (org.apache.kafka.clients.producer.internals.Sender)
[2018-01-22 19:46:08,664] WARN [Producer clientId=console-producer] Got error produce response with correlation id 370 on topic-partition test-produce-consume-3acks-0, retrying (1 attempts left). Error: NOT_ENOUGH_REPLICAS (org.apache.kafka.clients.producer.internals.Sender)
[2018-01-22 19:46:08,766] WARN [Producer clientId=console-producer] Got error produce response with correlation id 371 on topic-partition test-produce-consume-3acks-0, retrying (0 attempts left). Error: NOT_ENOUGH_REPLICAS (org.apache.kafka.clients.producer.internals.Sender)
[2018-01-22 19:46:08,867] ERROR Error when sending message to topic test-produce-consume-3acks with key: null, value: 68 bytes with error: (org.apache.kafka.clients.producer.internals.ErrorLoggingCallback)
org.apache.kafka.common.errors.NotEnoughReplicasException: Messages are rejected since there are fewer in-sync replicas than required.
[2018-01-22 19:46:18,556] WARN [Producer clientId=console-producer] Got error produce response with correlation id 373 on topic-partition test-produce-consume-3acks-0, retrying (2 attempts left). Error: NOT_ENOUGH_REPLICAS (org.apache.kafka.clients.producer.internals.Sender)
[2018-01-22 19:46:19,158] WARN [Producer clientId=console-producer] Got error produce response with correlation id 374 on topic-partition test-produce-consume-3acks-0, retrying (1 attempts left). Error: NETWORK_EXCEPTION (org.apache.kafka.clients.producer.internals.Sender)

... and when kafka is scaled back it silently resumes and the test goes back to Ready.

The two "-bootstrapbrokers" tests haven't given any clues for #132. They too get the occasional "Receive failed: Disconnected".