node: New relay configuration for nodes

Relay now has three values: "always", "never" and "auto".

The first two operate like the previous `true`/`false`. The
new (default) value turns relaying on for nodes with public (external)
addresses and off for nodes without. This should reduce redundant traffic on
the network, that was causing the rate limiters to trigger.

radicle-httpd/src/api/v1/profile.rs

@@ -92,7 +92,7 @@ mod routes {
                   "tor": null,
                   "network": "main",
                   "log": "INFO",
-                  "relay": true,
+                  "relay": "auto",
                   "limits": {
                     "routingMaxSize": 1000,
                     "routingMaxAge": 604800,