feat: Support typed params in routes

I mean, do something like:

``` js
app.route('/:an_id{number}');
app.route('/:another_id{string}')
```

which is roughly equivalent to use regex in each case, but the shorthand above is clearer and allows `req.params` to properly type the params, fi: `req.params.an_id` would be a number instead of a string.

Thanks