Add JavaDoc to KafkaContainer

Author: bsideup

modules/kafka/src/main/java/org.testcontainers.containers/KafkaContainer.java

@@ -4,6 +4,10 @@
 
 import java.util.stream.Stream;
 
+/**
+ * This container wraps Confluent Kafka and Zookeeper (optionally)
+ *
+ */
 public class KafkaContainer extends GenericContainer<KafkaContainer> {
 
     public static final int KAFKA_PORT = 9092;
@@ -79,4 +83,4 @@ public void start() {
     public void stop() {
         Stream.<Runnable>of(super::stop, proxy::stop).parallel().forEach(Runnable::run);
     }
-}
+}