DRILL-6625: Intermittent failures in Kafka unit tests
Unit test changes to fix intermittent kafka producer and consumer errors.
- Increase the value of REQUEST_TIMEOUT_MS_CONFIG to accomadate slower systems.
- Increase the value of producer RETRIES_CONFIG to 3 (from 0).
- Prevent producer to send duplicate messages due to retries by enabling Idempotent producer.
- Increase consumer poll timeout (from 200 ms).
- The design of `TestKafkaSuit` is very similar to design of `MongoTestSuit` and hence would require changes similar to the ones made in [storage-mongo/pom.xml](https://github.com/apache/drill/pull/923/commits/f5dfa56f33a46b92e2f9de153d82a16a77642ddf#diff-e110e2cbfd77d27e85d5121529c612bfR83).
- Current behavior is surefire runs test classes twice - once as a part of `TestKafkaSuit` and the other by directly running classes. To prevent the latter from happening, changes were made in `pom.xml` for `storage-mongo` plugin.
closes #1463
