Fix for OOIION-636 - Patches for the scenario where we have multiple uns instances 

* Just as the notification workers do, a subscriber in UNS now listens
for the reload user info event that gets published anytime a create, update
or delete method is used in UNS. The callback used by the subscriber reloads
the user info dictionaries from the resource registry the same way the 
notification workers do. This ensures that all instances of the UNS can reload the
user info from the resource registry in a common way whenever there has been a change in the notifications.

Now the notification workers and the UNS have a common framework for reloading the user info dictionaries.