Add a named group box for lists if element type not in implementedListDescriptors

For an ARON type containing:

            <ObjectChild key='traj_id_above_box'>
                <int32/>
            </ObjectChild>

            <ObjectChild key='trajectories_directory'>
                <armarx::arondto::PackagePath />
            </ObjectChild>

            <ObjectChild key='trajectory_under_box_to_above_rh_filename'>
                <string/>
            </ObjectChild>
            <ObjectChild key='trajectory_under_box_to_above_rh_default'>
                <List>
                    <armarx::arondto::FramedPose />
                </List>
            </ObjectChild>

            <ObjectChild key='trajectory_under_box_to_above_lh_filename'>
                <string/>
            </ObjectChild>
            <ObjectChild key='trajectory_under_box_to_above_lh_default'>
                <List>
                    <armarx::arondto::FramedPose />
                </List>
            </ObjectChild>

Before:

After:

The same change could probably applied to visitDictOnEnter()