New worklof for getting admins

IMPORTANT changes:
 - create new methods in Facilities, Groups and Vos managers for getting
   admins, richAdmins and authorizedGroups
 - deprecated set for all old methods in Facilities, Groups and Vos
   managers
 - add methods for working with othe than voadmin role to Vos Manager
   Impl (VoObserver and TopGroupCreator)
 - create new methods in AuthzResolver for uniform workflow with getting
   admins
  - method getRichAdmins
  - method getAdminGroups
 - create two new exceptions needed for working with admins and their
   roles
 - add all new methods to RPC
 - deprecated set for all these old methods in RPC

Less Important changes:
 - remove some not used Imports in modified files
Wouldn't be better to use EntityNotExistsException instead all these *NotExistsExceptions?