Close bld/OSG floor: OSG 3.4.1 from source + port osgQt to Qt6 + wire BgViewer dtEntity

Migrate BuildingViewer (16 files: DDS members, m_logger inits, QOpenGLWidget); gui:3:bld.info + gui:3:bdv now load

qt6-after/qt6-migrated-legatus/Lts/Plugins/BuildingViewer/Common/bdv_dds_controller.h

@@ -89,7 +89,7 @@ class BuildingViewerDdsController : public QObject
 
     inline bool isOutdatedPosition(const ParticipantManagement::ParticipantPosition& position) const
     {
-        return position.participantId() <= 0 || isOutdatedPosition(position.sampleTime());
+        return position.participantId <= 0 || isOutdatedPosition(position.sampleTime);
     }
 
     bool calcBaseCoordinate(const QMap<qint32, InfrastructureManagement::MainStructureElement>& mseMap);