"Enabling Translation" example should not use meta catalogs

Currently the first example showing how to use translations (http://doc.qt.io/qt-5/internationalization.html#enabling-translation) instructs to use the meta catalogs (qt_xx.qm) which were created to ease porting effort from Qt4.

Problem with the meta catalogs are that they depend on translations for now deprecated modules (qtquick1, qtscript) that might not be installed in the system (QTBUG-69146), which causes loading of the translation to fail (which is also not checked in the example).

Instead of the meta catalogs, the example should use the modularized translation files.