Implement all agreed changes in KafkaRollerST,  

KafkaRollerST

• testKafkaRollsWhenTopicIsUnderReplicated
  • Add producer consumer checks
  • investigate logging/warning or other steps done when topic spec claims it is to have more replicas than is specified number of total kafka brokers. 

RollingUpdateST

• testRecoveryDuringKafkaRollingUpdate
  • merge test  with testKafkaPodPending
• testManualKafkaConfigMapChangeDontTriggerRollingUpdate
  • check also change of used (by the Operator) data in given config map, instead of simplly adding new one.