configs/qemu-*: add host-qemu-system

Such config allows to setup gitlab tests for various
qemu architectures (x86, mips, nios2, microblaze, ..., etc)
using the same Qemu version.

Signed-off-by: Jugurtha BELKALEM <jugurtha.belkalem@smile.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>