Deny CLI export/import journal if JDBC persistence storage is configured

As it is written in analysis document [1] for EAP7-591, journal import/export command is not supported for JDBC persistence storage because Artemis doesn't provide any management operation for it.

Currently the operation still exports data from (or imports to) local file journal even the JDBC storage is configured. The operations should be denied in this case or there should be warning which will inform admin that this is not export that he wants.

[1] https://developer.jboss.org/wiki/DevAnalysisForEAP7-591-ProvideSupportForMessagingJDBCPersistence-storeInEAP