Revert "Make trivial use of new SQLiteConnection class"

This reverts commit 1a359380. It is needed because this commit breaks the reading of .db files on MacOS. i.e. in gmex the following error message is thrown: VP1QtApplication: Error '/Users/mariba/Atlas/GeoModel_package/GeoModel/GeoModelIO/GeoModelDBManager/src/GMDBManager.cpp:1100 --- [SQLite ERR] (loadGeoNodeTypesAndBuildCache) : Error msg: no such table: GeoNodesTypes' sending event '11QTimerEvent' to object '' ('6QTimer')