Add overview scene with lit cells pattern
This adds default device scene with lit cells pattern. The DetectorCellsWidget (see https://git.xfel.eu/karaboDevices/guiextensions/-/merge_requests/128) is used to represent lit cells pattern.
This adds default device scene with lit cells pattern. The DetectorCellsWidget (see https://git.xfel.eu/karaboDevices/guiextensions/-/merge_requests/128) is used to represent lit cells pattern.