Add a sample KafkaCluster CR with self.healing enabled in Cruise Control

[amuraru]

Is your feature request related to a problem? Please describe.

Currently the operator is not enabling Cruise Control self-healing (ability to continously evaluate the configured goals and balance the kafka load).

Describe the solution you'd like to see we should add a sample file in https://github.com/banzaicloud/kafka-operator/tree/master/config/samples to show how the user can enable this via KafkaCluster CR

Describe alternatives you've considered N/A

Additional context N/A