geoip-functions.pl: Re-write code to lookup the iso country code of a given IP-address.

geoip-functions.pl: Re-write code to lookup the iso country code of a given IP-address.

Drop the usage of the old legacy GeoIP perl module which was not able to handle the
new GeoLite2 databases.

Write some code to directly access the databases and extract the required data.

Usage of the GeoIP2 perl module would provide a lot of more functionality which is not
used/needed. Unfortunately ir requires at lot of additional perl modules which are
not available on IPFire and would only be build and shipped for this module. Buildig all
of them will slow down the entire build process, mess up the system and requires a lot
more space on disk.

Fixes #11962.

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>