perl-functions.eclass: add perl_has_module_version

perl-functions.eclass: add perl_has_module_version

This is a utility for runtime checking if a module of a given version
is installed from the perspective of Perl, whos opinion could be
different than portage in the event of perl-core/* dual life effects
shortly after a major Perl upgrade.

Use this only if perl_has_module is insufficient, as the overheads
and risk of side effects from this approach are high, given the module
has to be actually loaded for the version comparison to happen.

exits "true" if Perl has the given module installed at the given
version ( or later ), exits "false" otherwise.