Integrate MaxMind GeoLite2 DB for geolocalisation

[teon]

1. We have registered to MaxMind with: community@defguard.net - from where we can download get GeoLite2 City (for development purposes - we **cannot distribute it).
2. Implementation should cover:

• adding to docker/kubernetes the PATH to the database file - if the path is empty (or file wrong) disable GEOIP
• adding Geolocalisation chapter in the documentation, informing:
  • that we support for now MaxMind GeoLite2
  • to download and enable GeoIP in defguard one must register and download the database from https://www.maxmind.com/en/geolite2/signup
  • how to configure the path to database in deployments

[wojcik91]

https://crates.io/crates/maxminddb

Some reference for implementation: https://fasterthanli.me/series/building-a-rust-service-with-nix/part-8