Added more monitoring hooks and connect ManagedComponent implementations

As part of the MODE-637 work, a number of managed components were added to the 'deploy/jbossas/modeshape-jbossas-service' project. These classes are POJOs that declare the @ManagementObject annotation and thus expose their @ManagementProperty and @ManagementOperation through the JBoss ProfileService. The top-level object is the ManagedRepository object that has to be declared in the jboss-beans.xml. This object, however, dynamically creates upon request immutable objects for the various services and nested components. These are then exposed to the JOPR/JON plugin through the ProfileService.

This task is to implement the various @ManagementProperty and @ManagementOperation methods by measuring the appropriate metric or characteristic on the JcrEngine instance (or its nested services and components). This task will also have to modify the JcrEngine and its components to expose this information. Consider defining new interfaces (perhaps in the org.modeshape.jcr.monitor package of 'modeshape-jcr') if that adds value. Also consider how we'll measure various metrics, like "# of sessions" (i.e., do we need to have a running average mechanism?).

Update: Some of these are already implemented, but we still need to implement the remainder.