Add qemu-utils for qemu-img

The virtualbox image for the sdk is created by qemu-img add that to the
docker image.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Reviewed-by: Héctor Orón Martínez <hector.oron@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D7248