Mark the public org.apache.activemq.artemis.* modules as private, add a usage note.

There are 3 Artemis-related modules that do not have the jboss-api=private setting that marks them as inappropriate for direct use by deployments:

org/apache/activemq/artemis/journal

org/apache/activemq/artemis

org/apache/activemq/artemis/protocol/hornetq

AIUI the reason these don't have the setting is not because deployments can directly use them, but rather because they provide API that can be used for user-provided modules that provide impls of messaging-activemq subsystem configuration plug points (e.g. used in classname/module name attribute pairs.)

Task is to add the jboss.api=private setting so these get flagged up if used by deployments. Add a code comment explaining the supported use.  Comment should include a string that would be used consistently in the module.xml file for such cases, to make it easy to find such cases by grepping.