MITK modules should get dedicated Doxygen groups just like MITK plugins. The group definitions should be located in the module directory.
Needs core modification because I would like to move most of the Documentation/Doxygen/API/Groups/* files to Core/Documentation/Doxygen/Groups.
No C++ code will be modified.
The module documentation inside the corresponding Doxygen group will be used for the CoreApp QM architecture document (linking to it).