greatly simplify the way peers are created in Vivaldi AS

greatly simplify the way peers are created in Vivaldi AS

We used to create a mini cluster for each added peer, which is useless
since they are already in a Vivaldi AS. So instead, add the link
up&down to the Vivaldi containing AS.

This way, we can hide again the netcard of the AsImpl, that was made
public only a few commits ago.