Integrate Tor BSD Diversity Project's statistics into Tor Metrics

The Tor BSD Diversity Project (https://torbsd.org/) maintains some scripts to produce statistics about diversity in the Tor network. We should look to see if there are statistics here that are already handled by Tor Metrics or if there are analysis that we could be doing but currently we're not.

I would see this as an "upstreaming" effort, that would increase the benefit that can be realised from the analyses by making them more easily discoverable and available to other groups (e.g. a potential future "Tor IRIX Diversity Project" should not have to duplicate this effort).

https://github.com/torbsd/tdp-onion-stats contains the scripts that are currently used.