Gui: Use FreeCAD Theme only for FreeCAD stuff
Qt6: QLocale::countryToString and QLocale::country() are deprecated since Qt 6.6
Qt6: Several methods of QMouseEvent are deprecated since Qt 6.0
Qt6: QColor::setNamedColor is deprecated since Qt 6.6
Gui: Force OpenGL rendering for main window
StartPage: Make sure to pass a container widget to the QScrollArea
MSVC: Fix several compiler warnings
Core: Placement dialog