FEATURE: allow disabling private IPs

When forcing the internal IP to "" or "-", private IPs won't be used.

pkg/mesh/topology.go

@@ -83,6 +83,8 @@ func NewTopology(nodes map[string]*Node, peers map[string]*Peer, granularity Gra
 		switch granularity {
 		case LogicalGranularity:
 			location = logicalLocationPrefix + node.Location
+			// Put node in a different location, if no private
+			// IP was found.
 			if node.InternalIP == nil {
 				location = nodeLocationPrefix + node.Name
 			}