Poc to implement unit testing of the helm charts

As the charts are becoming more and more complex and critical in the infra, it could be useful to have some protection against any regressions when an update is done.

These tests are only to test the generation part of the helm charts.
It's possible to test the validity of the descriptor with kubeval but I didn't dig to far yet.

Both tools look not to complex to integrate in a CI pipeline as it's only a docker command / helm plugin to install.

@olasd @ardumont WDYT? do you think it's worth continuing in this direction?