feat(p2p): allow to run multiple clusters in the same p2p network (#3128)

feat(p2p): allow to run multiple clusters in the same network

Allow to specify a network ID via CLI which allows to run multiple
clusters, logically separated within the same network (by using the same
shared token).

Note: This segregation is not "secure" by any means, anyone having the
network token can see the services available in all the network,
however, this provides a way to separate the inference endpoints.

This allows for instance to have a node which is both federated and
having attached a set of llama.cpp workers.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>