Using find_next_iface_id we get a valid VLAN name.
This way, inserting a vlan raw device is still required (but everything that is
inserted so far is valid).
Signed-off-by: Dominic Jäger <d.jaeger@proxmox.com>
We usually choose default values that are valid input for the field.
interfaceX.1 is rejected by the API.
Instead, use a tooltip to demonstrate possible valid inputs for the field.
Signed-off-by: Dominic Jäger <d.jaeger@proxmox.com>
