static app (app, options) {
    Auth.#app = app;
    app.use(Auth.#ppChecker);
    app.use(Auth.#authRouter);

    app.post('/api/login', bodyParser.urlencoded({ extended: true }));
    app.use(Auth.doAuth);

    if (Auth.#app && Auth.#authConfig?.trustProxy !== undefined) {
      Auth.#doTrustProxy();
    }
  }
Set up the app.use() calls for the express application. Call in chain where
auth should be installed.