Current ManagedConnectionFactory, AdminObject can not be displayed under RAR resource in RHQ plugin inventory because of WeakReference of JCA object in management model.

The solution is:
1. Create a ManagementRepositoryMeta class to wrap needed information like class name of javax.resource.spi.ManagedConnectionFactory and associated rar unique id in the tree structure
2. Add a method: getManagementRepositoryMeta() to Discover interface so that the ManagementRepositoryMeta can be initialized when discovers ManagementRepository