Block known datacenter ranges flooding Phabricator

Phabricator instances receive a very large number of requests
from datacenter servers.

Pending Anubis implementation, this temporary block will mitigate
the current server load.

The ranges2geo.py utility allows to convert a text file containing
CIDR ranges into a geo block for ngx_http_geo_module.

Test Plan: Deploy on docker-002

Reviewed By: Duranzed

Differential Revision: https://devcentral.nasqueron.org/D3947