Adapt custom attributes in ONE templates to current use
The goal is to simplify the creation of a k3s cluster and to better reflect how the project eole3 handle the creation of a cluster and the installation of its kubernetes components.
- Remove the KUBEAPPS_DNS_NAME parameter (we don't use kubeapps and if we wanted to, we would use eole3/tools).
- Remove the LE_EMAIL parameter (we don't use it and again, if we wanted to, we would use eole3/tools).
On the k3s-cluster-app project, these 2 parameters are "used" in a dead code.
Bonus: change default domain to eole3.ac-test.fr
Don't forget to update the doc.