HHH-7993 Support jar scanning in OSGi 

@brmeyer I'm proposing some slight modifications. There was a slight misunderstanding about the BundleWiring API. There is a separate BundleWiring for each OSGi bundle, so in order to scan for classes you need to use the wiring for the persistence bundle, otherwise you end up repeatedly scanning the hibernate-osgi bundle instead.

Otherwise it all looks good!