decouple generated kubeconfig server url from ha registration ip

[poblin-orange]

As of v124.7, when using multi master ha mode.
The bosh release has a single setting property to set registration ip.

In particular uses cases, we want to have a separate setting for fixed registration ip (use when a node is added, live translated as a set of ip by k3s), and a property for api access (typically a dns name, hosted by an external loadbalancer un related to fixed registraion ip)

Moreover, the fixed registration ip is unclear with ha embeded etcd.

• bootstrap k3s server start with --cluster-init
• other k3s server reference https://:6443
• k3s agent use https://<master_vip>:6443

Need to untangle wrt the different role, and have a clear mapping