[fuel] verify: Multiarch, docker build step

[fuel] verify: Multiarch, docker build step

Rework Fuel verify jobs:
- split 'fuel-verify' into per-arch jobs (amd64 and arm64):
  * for now, arm64 jobs are non-voting;
- add 'docker-build' phase job:
  * the docker build job will run on the same virtual POD jump host
    as the deploy, to bypass the need of pushing to a (public)
    Docker hub registry - this might be refactored later to resemble
    the old Fuel ISO build workflow where the artifacts built during
    verify are the ones actually promoted - with the current method
    the final build & tag (ran on OPNCI CI build servers) might yield
    different results due to different docker build cache states;
  * the locally built container image is tagged with the 'verify'
    designator and not pushed to a public registry, only consumed
    during verify's job 'deploy-virtual' phase;

JIRA: ARMBAND-401
JIRA: FUEL-383

Change-Id: I9b0d8079e759cdc895260219a8a4989411c995ff
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>