fuel, armband: verify jobs: Enable virtual deploy

fuel, armband: verify jobs: Enable virtual deploy

Enable virtual deploy phase for verify multijob for both projects.
Since fuel-defaults already define SSH_KEY param, drop it from
individual jobs.

Fuel:
- drop merge jobs, which used to perform virtual deploys based on
  ISO created during verify job;
- cleanup fuel-download-artifact (rm support for merge/verify);

Armband:
- while at it, remove "opnfv-build-enea-defaults", preparing for
  arm-build2's retirement.

JIRA: FUEL-278
JIRA: FUEL-287

Change-Id: I354d72d88187e41070f44c723ccc651a0bb9b021
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>