urlapi: URL decode percent-encoded host names

urlapi: URL decode percent-encoded host names

The host name is stored decoded and can be encoded when used to extract
the full URL. By default when extracting the URL, the host name will not
be URL encoded to work as similar as possible as before. When not URL
encoding the host name, the '%' character will however still be encoded.

Getting the URL with the CURLU_URLENCODE flag set will percent encode
the host name part.

As a bonus, setting the host name part with curl_url_set() no longer
accepts a name that contains space, CR or LF.

Test 1560 has been extended to verify percent encodings.

Reported-by: Noam Moshe
Reported-by: Sharon Brizinov
Reported-by: Raul Onitza-Klugman
Reported-by: Kirill Efimov
Fixes #7830
Closes #7834