FWREZNETxxx - Modelling - also externally request all app roles used in interfaces

[tpurschke]

this could improve the awkward situation where an app using an interface creates or even modifies a network group belonging to another owner (interface owner).

this needs to be planned properly if we want to

• avoid any manipulation by interface users
• make sure an interface change can be initiated by the interface owner - need to think about the communication between interface owner and user