Add city level geoip database to Belenos from multiverse

The upstream package install script come utility has been modified to also download the compressed (gz,xz,zip) source CSVs to the package's directory in /usr/share/doc.  It is then possible to modify the database by editing those and rebuilding the databases with /usr/lib/geoip/geoip-generator from package geoip-bin.

The 'new' code is simply a refactored copy of the binary download code already in the install/utility script.

See https://trisquel.info/en/issues/13927

See merge request !67