JMX enable the BulkImportStatus bean

[pmonks]

Migrated from https://code.google.com/p/alfresco-bulk-filesystem-import/issues/detail?id=11

While monitoring via the status Web Script is reasonably functional, it would be ideal if the backing bean (the Bulk Import Status bean) was itself JMX enabled, allowing monitoring not only via HTTP calls, but also via JMX.