NNG v2.0 simplifies `parse_url()` output

Specifically there will be no:

-  `rawurl` - the same as the input string
- `host` - the same as `hostname[:port]`
- `requri` - the same as `path[?query][#fragment]`

As these are duplicated fields that can be derived from the other outputs.

We can adapt to this now and make it a breaking change earlier rather than later.