Addresses one of the points in #14162
# Description
Factors out part of the `url::build_query::to_url` function into a
separate function `url::query::record_to_qs()`, which is then used in
both `url::build_query` and `url::join`.
# User-Facing Changes
Like with `url build-query` (after #14073), `url join` will allow list
values in `params` and behavior of two commands will be same.
```nushell
> {a: ["one", "two"], b: "three"} | url build-query
"a=one&a=two&b=three"
> {scheme: "http", host: "host", params: {a: ["one", "two"], b: "three"}} | url join
"http://host?a=one&a=two&b=three"
```
# Tests + Formatting
Added an example to `url join` for the new behavior.
719d9aa83c