Ever since PublicSuffixData was created, it was using "no star rule"
matching, which is what is needed for the address bar to distinguish
between a domain and a search. URL::Host on the other hand requires
the fallback star rule. Which rule is needed depends on the use case
of the PSL. Support both use cases by a flag in PublicSuffixData.
Replace the generated public suffix table and custom matcher with a
direct LibURL PublicSuffixData implementation backed by libpsl. This
drops our PSL download/generator path and uses the same library already
used by libcurl.
Performance is comparable before and after, while LibURL binary size
is smaller.
Move the registrable-domain helper from URL into PublicSuffixData and
name it find_matching_registrable_domain().
This keeps it alongside find_matching_public_suffix(), making it clear
that both APIs only return results matched from the PSL data, while
Host::public_suffix() implements the URL Standard fallback to the
top-level domain.
