Update 2.4.0 resource files for sasl integration

Author: dpkp

servers/2.4.0/resources/kafka.properties

@@ -24,6 +24,8 @@ broker.id={broker_id}
 listeners={transport}://{host}:{port}
 security.inter.broker.protocol={transport}
 
+{sasl_config}
+
 ssl.keystore.location={ssl_dir}/kafka.server.keystore.jks
 ssl.keystore.password=foobar
 ssl.key.password=foobar

servers/2.4.0/resources/kafka_server_jaas.conf

@@ -0,0 +1,4 @@
+KafkaServer {{
+    {jaas_config}
+}};
+Client {{}};