feat: Adds IPv6 disabling feature (#803)

* Allow disabling IPv6

Simply ignores any IPv6 addresses in the lease and doesn't offer them to the RPC
Also fixed display issue for IPv6 link local address.
Fixes https://github.com/orgs/jetkvm/projects/7/views/1?pane=issue&itemId=122761546&issue=jetkvm%7Ckvm%7C685

* Don't listen on disabled addresses in mDNS or web server.

* We have to set the IPv4 and IPv6 modes on the server.

mdns.go

@@ -13,10 +13,7 @@ func initMdns() error {
 			networkState.GetHostname(),
 			networkState.GetFQDN(),
 		},
-		ListenOptions: &mdns.MDNSListenOptions{
-			IPv4: true,
-			IPv6: true,
-		},
+		ListenOptions: config.NetworkConfig.GetMDNSMode(),
 	})
 	if err != nil {
 		return err