Add explicit QtDoc dependencies to qtdoc/examples/demos

Augment the metadata for Application Examples in qtdoc.git with information on Qt dependencies.

For the dice example:

\meta {QDocDependencies}{QtQuick3D,QtQuick3DPhysics,QtMultimedia,QtSensors}

This would in turn Qt Creator to check whether the corresponding documentation is available (and by extension, also the API / libraries).