Make mountpoint-registrar.properties configurable

Introduce env variables for kafka settings in mountpoint-registrar.properties

 
[strimzi-kafka]
strimziEnabled=${SDNR_KAFKA_ENABLED}
bootstrapServers=${SDNR_KAFKA_BOOTSTRAP_SERVERS}
securityProtocol=${SDNR_KAFKA_SECURITY_PROTOCOL}
saslMechanism=${SDNR_KAFKA_SASL_MECHANISM}
saslJaasConfig=${SDNR_KAFKA_SASL_JASS_CONFIG}
 

previous settings should be set as default.

Change csit tests:

remove file: csit/scripts/sdnr/docker-compose/sdnr/mountpoint-registrar.properties

add env variables and remove file mount to file above in
csit/scripts/sdnr/docker-compose/docker-compose-single-sdnr.yaml
SDNR_KAFKA_ENABLED=true
SDNR_KAFKA_BOOTSTRAP_SERVERS=kafka:9092