Write script that helps with fd related overload

As we have seen in analysis#24 (comment 2791135) there are quite some spurious fd overload related hits, even if we take only an 18h overload window (instead of the 72h one). However, as we've also seen there are some persistently overloaded relays among them.

We should write a script that is doing the analysis for us, daily, and saves every day the fingerprints that have shown up for the past X days (X could be something like 3 or 5 maybe) for someone reaching out to affected operators.