MEDIUM: httpclient: remove url2sa to use a more flexible parser

MEDIUM: httpclient: remove url2sa to use a more flexible parser

The httpclient DNS resolver will need a more efficient URL parser which
splits the URL into parts and does not try to resolve.

httpclient_spliturl uses the http_uri_parser in order to split the URL
into several ist.

The result of the function host part is then processed into str2ip2(),
and fails if it it not an IP, allowing us to resolve the domain later.