WIP: Add cern_metachart to magnum
This is still a preview as we use Git (non existent in the tiller pod) to download the repo.
The ideal way would be to download the chart locally by means of a helm repository.
- Add magnum labels cern_metachart_enabled and cern_metachart_version to control CERN's magnum meta-chart installation
- Add eosxd and kubemonkey enabled magnum labels to enable/disable respective subchart installation
Ref. OS-9770