Feature request: parse port

I'd like to propose to extend `.parse()` to also return the port, like so:

```javascript
tldjs.parse("example.com:1234");
// {
//     domain: "example.com",
//     hostname: "example.com",
//     isIp: false,
//     isValid: true,
//     publicSuffix: "com",
//     subdomain: "",
//     tldExists: true,
//     port: 1234  // <-----------------
// }
```