Draft: Load default panel orientation
DRM quirks contains a property for the defualt orientation for a montior. This is used for built-in complete devices rather than external monitors.
This is set in the Output constructor where we also load the default mode. This means for the first run kwin will show the right setting but also provide the correct initial value for OutputDevice so kscreen will implicitly use it for future operations.
If a different transform is set in kwin's screen config or kscreen it will then be overriden.
Draft as untested on such a device