AdminActor should be replaced with workers

(User Story, Closed -> Fixed, Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Scalability
Summary: This was originally "AdminActor should be a Cluster Singleton", but I realized that that's just wrong. There is nothing there that needs to be even long-lived, so the right answer is to just replace it with temporary focused Actors that do what is needed then go away.