Add a notice if we're missing data for a lookup
Turns out the the exit scanner had an issue between April 25 and 29, 2019. If somebody looks up their exit IP address during that time, they won't be listed in the results. I know of one case where this is now potentially an issue.
Let's think about adding a notice if we're missing data for part of a lookup period, including exit lists and maybe also consensuses. This is different from having no data at all, it's about missing some data only.
First step will be to refine the (already quite complex) query to return whether we have sufficient or insufficient data, possibly but not necessarily with exact timestamps of available data.
Second step will be to include the notice in the website, first in English and then in translated languages.
Third step will be to release and deploy all this.
I'll work on this, but I'm putting it into needs_review to discuss the idea first.