CI: deploy-cache STUB: ci/deploy.sh -C arg def

CI: deploy-cache STUB: ci/deploy.sh -C arg def

Prepare support for caching deploy artifacts, like bootstraps and
target images, which take a lot of time at each deploy to be built,
considering it requires a cross-debootstrap via qemu-user-static and
binfmt.

NOTE: THIS IS JUST A STUB. Full implementation will be cherry-picked
from master after proper testing, but we need to implement arg
support so we don't break on unknown "-C" arg passed down from Releng.

JIRA: ARMBAND-172

Change-Id: Id2229767eb423df11784bb7621499902387d2f69
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>