[ci] add nftables integration tests for dbip and maxmind

[chr0mag]

Both the dbip and maxmind datasets are updated weekly. It would be nice to have an integration test automatically run weekly that does the following:

• build dbip and maxmind nft sets for both ipv4 and ipv6
• load each set into nftables, use them as part of a rule, and start the service to ensure the sets are compatible

The following python-nftables bindings might help:

• https://ral-arturo.org/2020/11/22/python-nftables-tutorial.html
• https://github.com/aborrero/python-nftables-tutorial
• https://git.netfilter.org/nftables/tree/py/nftables.py

This library is included as part of the Archlinux nftables package, and packaged separately in Ubuntu. Executing the tests from Python would make it simple to include in the existing python-tests as part of the pytest run.

Alternatively a Bash script could be used to perform the same task.