[enh] Use configuration for API network listening

index.ts

@@ -69,7 +69,13 @@ Duniter.run([{
             ':gva:' + conf.pair.pub.substr(0, 6))
           return {
             startService: async () => {
-              if (!conf.gva || conf.gva.upnp) {
+              if (conf.gva) {
+                // Static usage of port + host, no UPnP
+                app = gvaHttpListen(server,
+                  conf.gva.port || DEFAULT_GVA_PORT,
+                  conf.gva.host || 'localhost')
+              }
+              else if (!conf.gva || conf.gva.upnp) {
                 // Using UPnP
                 const { available, host, port } = await api.startRegular()
                 if (available) {