Add support for Kubernetes new Chart format

[dkapanidis]

Helm is now part of Kubernetes and so are Charts.

There is a refactor of how the Charts are now distributed, the new specs are here.

The main difference with the previous format is that manifests are now templates (in go format) with default configuration values taken from the values.yaml file.

Integrating this with elastickube would give a good interface to manage charts through web UI.

A workable demo is prepared at https://github.com/harbur/elastickube/tree/add_new_chart_format using tide as a CLI to render the charts before injecting them to the database (which means no dynamic variables are possible yet)