* net/url: implement url encoding (RFC 3986)
Implement url percent-encoding and -decoding functions according to RFC
3986. Add unit tests.
Link: https://datatracker.ietf.org/doc/html/rfc3986
* net/url: ensure correct encoding of URL components
Add encoding and decoding methods to the Url struct components according
to RFC 3986.
An Url can be parsed from a String with `new_parse()` or `temp_parse()`.
The parsed fields are decoded. The only field that is not decoded is
`raw_query`. To access the decoded query values, use
`Url.query_values()`.
`Url.to_string()` will re-assemble the fields into a valid Url string
with proper percent-encoded values.
If the Url struct fields are filled in manually, use the actual
(un-encoded) values. To create a raw query string, initialize an
`UrlQueryValues` map, use `UrlQueryValues.add()` to add the query
parameters and, finally, call `UrlQueryValues.to_string()`.
---------
Co-authored-by: Christoffer Lerno <christoffer@aegik.com>
