package/zip: add host-zip

Make the host variant of zip available.  This can be useful in
post-{build,image} scripts.

Signed-off-by: Martin Bark <martin@barkynet.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>