Lookup user for crossbar authorization
Lookup user for crossbar authorization

Crossbar authorization function decides based on topic name:
yunity.public.* is allowed for everyone to subscribe
yunity.user.<userid>.* is only allowed to subscribe, if the session
belongs to the user named in the topic.
Use the SharedSessionData to lookup the user for a session.

yunity/foodsaving-backend,yunity/yunity-core,yunity/foodsaving-backend,yunity/yunity-core,yunity/foodsaving-backend