Introduce a geoloc package that stores CIDR-to-country mappings in
PostgreSQL using the native cidr type with a GiST index for fast
containment lookups. Data comes from the ipverse/country-ip-blocks
dataset added as a git submodule.
A standalone geoloc-import command reads the TXT files from disk
and bulk-loads them via COPY. probod wires the service and logs a
warning when the table is empty.
Signed-off-by: Émile Ré <emile@getprobo.com>