GET /teams from RTS instead of config.json

Now that the RTS contains config for teams, use GET /teams to get that information so that users will see be able to register as a team (but not yet auto-join rooms, be sent to welcome page or be tracked as a referral).

src/RtsClient.js

@@ -0,0 +1,15 @@
+const q = require('q');
+const request = q.nfbind(require('browser-request'));
+
+export default class RtsClient {
+    constructor(url) {
+        this._url = url;
+    }
+
+    getTeamsConfig() {
+        return request({
+            url: this._url + '/teams',
+            json: true,
+        });
+    }
+}