Issue with setting Express options

[cciocov]

Up until 5.0.0-pre.15 I was able to use something like this:

const app = express(feathers());
app.set('query parser', function customQueryParser(str) { ... });

After 5.0.0-pre.15 this is no longer possible and I tracked the issue to the fact that we call .use() on the express app during the express(feathers()) call, which forces Express to initialise its lazy router (and at this point the query parser setting has its default extended value. The code I'm talking about is:

  app.use((req, _res, next) => {
    req.feathers = { ...req.feathers, provider: 'rest' };
    return next();
  });

(starting on line 109 in packages/express/src/index.ts).

Previously (i.e.: up to 5.0.0-pre.15) this code used to be packages/express/src/rest.ts and would only execute on app.configure(express.rest()).

I would suggest we keep express(feathers()) as similar as possible (in terms of the effects on the Express app) as the original express() call that people use to create a plain Express app.