FluxV1: Helm deployments via private git repo do not deploy

[marekzan]

After switching to private repositories the helm-operator of fluxv1 is not able to sync the chart from the git repository if it is private. It is necessary to implement a mechanism so that the helm operator can read private chart repositories.

Possible solution: https://github.com/fluxcd/helm-operator/blob/master/chart/helm-operator/README.md#use-a-private-git-server