[DG-AM] Use cases AM

From the perspectives of the federation projects I am involved in I see following high-level use cases/constellations that have a need for attribute management: - C10: Delegated Identity Management (basic use case with IdP managing attributes) - C20: Service Provider Centric model (IdP provides attributes) - C32: Identity Federation - C33: Cross Border Identity Federation - C40: Attribute Provider separate from IdP - C41: Attribute Provider with RP (Canda Gov. use case) - C50: Enterprise user - C60: Subject Types (devices) - Rainer