Feature request: Record and show historical build queue length

I see some Rust users worrying about the length of the docs.rs build queue and thinking “docs.rs must be struggling” or “oh no my just-published crate is going to take forever to have docs”. And yet, the build queue can progress quite fast and is often empty — it’s just hard to tell that when you have noticed that it is long this moment.

I think it would be fun and educational if https://docs.rs/releases/activity had, in addition to the chart of releases per day, a separate chart of the minimum and maximum build queue length for each day. (It should be separate because its Y-axis doesn’t represent a releases/day throughput like the existing chart does.)

Start at the releases/activity page and inspect how its existing releases-per-day chart gets its data and is rendered. Determine where daily build-queue minimum and maximum values can be recorded and displayed as a separate chart; done means the page shows historical daily minimum and maximum queue lengths with an independent Y-axis.