Rework jobs/playbooks/roles

Current setup doesn't work that well when inheriting. I would like "all
my projects" to only inherit from the job which uses the
`run-test-command` playbook. Then, those jobs which need submodules,
should explicitly ask for that pre- playbook provided by
`git-submodules`.

In Zuul and Ansible, roles are the bits that are supposed to be shared.
As per corvus recommendation on IRC, let's use job variables to control
execution in a more fine-grained manner.

Change-Id: I48c13bff0be7cf796b75e5176774226fb3bb5cc8
9 files changed
tree: 3c6863218e5a526f8d29e4b65c406166b9bdc7ea
  1. README.md
  2. playbooks/
  3. roles/
  4. zuul.yaml
README.md

Zuul jobs specific to CESNET