Create "runtime only" resource for the WS endpoint information

The patch for AS7-698 introduced a call from a deployment unit processor into the management layer, in order to add some transient (i.e. not marshalled to xml) state about ws endpoints. We need to get this out of the core model and avoid the need for deployers to invoke management operations (TBH I'm not sure why this management op works at all.) To do that we need some better support for a true "runtime only" resource, one that has no representation in the model. At least a good example, so subsystem devs can see how to implement one. Such an example will likely fall out of the work on exposing the JDK platform mbeans via the management system, since those are purely runtime resources.

The part that needs to be demonstrated is how to override the global operation handling (e.g. read-resource, read-attribute, read-children-names on the parent resource), since the default handlers for those ops are built around reading the model.