CI/Jenkins stage 2 integration of vim-emu

Added Jenkinsfile and stage-test.sh to trigger vim-emu's
unittests using Jenkins. The stage-build script is a placeholder
since the installation is done during the container build
process (see Dockerfile). stage-archive is not yet done.

Requires the following change in the devops repository
to allow privileged container execution in stage_2:
https://osm.etsi.org/gerrit/#/c/5624/

Change-Id: Ib140294b68b70b03e66f0f5d2bc11cd19d8777ca
Signed-off-by: peusterm <manuel.peuster@uni-paderborn.de>