Review AS7 EndpointPublisherImpl integration

As a consequence of having moved the registration of endpoints into EndpointRegistry in the AS7 EndpointService, the JBossWS Shared Testsuite test for the EndpointPublisher fails due to the published endpoint not being registered. That's because the ServiceTarget is not available in that case, hence the EndpointService is not installed.
The endpoint publisher and its service needs to be reviewed to properly use a service target.