qt-webkit-kiosk: new package

Qt-webkit-kiosk is a simple browser working in kiosk-mode, powered by
QtWebkit. It provides a convenient way to deploy a full-screen browser
on embedded system platforms.

This commit adds the appropriate packaging to Buildroot, including an
option to deploy the provided sound files.

Signed-off-by: Jerome Oufella <jerome.oufella@savoirfairelinux.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>