[bugfix] Avoid 'IllegalArgumentException: Having a requried argument and a default value makes no sense' when calling 'jmxclient.sh --help'

Author: adamretter

exist-core/src/main/java/org/exist/management/client/JMXClient.java

@@ -256,17 +256,14 @@ private void error(Exception e) {
     /* connection arguments */
     private static final Argument<String> addressArg = stringArgument("-a", "--address")
             .description("RMI address of the server")
-            .required()
             .defaultValue("localhost")
             .build();
     private static final Argument<Integer> portArg = integerArgument("-p", "--port")
             .description("RMI port of the server")
-            .required()
             .defaultValue(DEFAULT_PORT)
             .build();
     private static final Argument<String> instanceArg = stringArgument("-i", "--instance")
             .description("The ID of the database instance to connect to")
-            .required()
             .defaultValue("exist")
             .build();
     private static final Argument<Integer> waitArg = integerArgument("-w", "--wait")