url: extend url.format to support WHATWG URL

Removes the non-standard options on WHATWG URL toString
and extends the existing url.format() API to support
customizable serialization of the WHATWG URL object.

This does not yet include the documentation updates
because the documentation for the new WHATWG URL object
has not yet landed.

Example:

```js
const url = require('url');
const URL = url.URL;
const myURL = new URL('http://example.org/?a=b#c');
const str = url.format(myURL, {fragment: false, search: false});
console.log(str);
  // Prints: http://example.org/
```

PR-URL: https://github.com/nodejs/node/pull/10857


Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>