CGI.pm will be removed in 5.22; install from CPAN on 5.20 and up

Perl 5.22 will remove CGI.pm from core; using the installed-from-core
version in perl 5.20 produces warnings.  On perl 5.20 and above,
increase the dependency to one that was never provded in core, to force
an install from CPAN.

Fixes I#29053.
Hide the CGI.pm "this is deprecated, install from CPAN" warnings

If other modules load CGI before we install the updated version, they
will get the in-core version, and trigger spurious deprecation warnings.
Quash deprecation warnings before loading to quiet this warning.
Merge branch '4.0/perl-5.19-cgi-deprecation' into 4.0-trunk