Add MaxMind GeoLite Country crawler

[m-appel]

Adds support for the free MaxMind IP geolocation database. This data is already integrated via the ihr.rov crawler, but our modeling has changed and geolocation is not really the purpose of the ROV crawler.

Separating this into its own crawler makes things more logical, so the country information is not imported by ihr.rov anymore.

Description

The imported data has pretty much the same format as the existing IPinfo crawler. Map GeoPrefix to Country nodes. Relationship properties are a bit different, but only included for completeness anyways.

Also removes the Country part from ihr.rov.

Motivation and Context

Currently we already include MaxMind data (although not all of it) via the ihr.rov crawler. However, this is a bit unclean and also uses the old model where we mapped BGPPrefix nodes to Country nodes. Separating these parts makes everything cleaner. We can also use it to compare IPinfo and MaxMind discrepancies.

How Has This Been Tested?

Tested the new crawler and also checked that ihr.rov still works.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[romain-fontugne]

Looks good to me, just a couple typos in the doc.