Removed obsolete and potentially problematic IDNA 2003 ("punycode")
encoding of international domain names in smart_urlquote() and Urlizer,
which are used (only) by AdminURLFieldWidget and the urlize/urlizetrunc
template filters. Changed to use percent-encoded UTF-8, which defers
IDNA details to the browser (like other URLs rendered by Django).
Backport of 29ba75e6e57414f0e6f9528d08a520b8b931fb28 from main.