Inconsistency and wrong definitions of requests/responses in proto files

Description

There are a few inconsitencies and wrong definitions in the proto files. For example (see screenshot) it is possible to add more than one PND ID in the GetPnd request, but it should only be possible to request and receive one object form this call. This kind of issue also applies for a few other requests (SBI, OND, etc.) and should be fixed there as well.

Expected Behavior

A method which implies to request only one object should return only one object and calls implying they return a set of objects should return a set of obejcts.

Possible Fix

• Change proto files according to correct expectations e.g. remove option of adding more than one PND ID to GetPnd and so on