Switch to r10k for deployment

By switching to r10k, we can leverage Puppetfile for external modules.
r10k will build a modules directory. All site specific modules are
placed in the site directory.

This requires us to change our puppet master configuration according to
https://github.com/adrienthebo/r10k#puppet-master-configuration, but we
don't manage puppet through puppet so it's not included in this patch.

Deployment of environments is done through the puppet-repos user, as
managed by ovirt_infra::puppet_deploy. Access is limited to the single
update command which in turn invokes r10k with the correct parameters.
It reads the global /etc/r10k.yaml and deploys accordingly.

Change-Id: I666317e14440d5544f6afc1f02d35fb518ebe345
Signed-off-by: Ewoud Kohl van Wijngaarden <ewoud@kohlvanwijngaarden.nl>