[Sprint 39] [master] XD-2333 Add Kafka integration test

  - Add kafka test support class that checks for kafka server availablity on localhost
     - This uses zk server available on default connect string `localhost:2181`
  - Add test for verifying kafka source and sink
     - having both the source/sink on the same test case will make sure the topic that
gets the data by kafka sink is actually read by kafka source
I've found this `ZKStringSerializer$.MODULE$` instead.
So, the code above will looks like:
````java
new ZkClient(ZOOKEEPER_CONNECT_STRING, 5000, 5000, ZKStringSerializer$.MODULE$);
````
However I made it just only with 1 sec to wait for connection to avoid long wait time for connection to ZK.
From other side your rule doesn't care about stopped zookeeper for the `org.I0Itec.zkclient.exception.ZkTimeoutException` on that `new ZkClient()`.

Or exception propagation to the target test-method is OK for XD?