Rewrite score calculation in Rust

[nicoburns]

Score recalc is pretty slow currently. Slow enough that I left it and came back to it several times and it still wasn't done. We should consider rewriting it in Rust for better performance. Such an implementation could:

• Use streaming parsing for the JSON (and LZMA decompression) using a custom serde Deserialize implementation, avoiding allocating huge arrays of test results. This could be done both for top-level tests and sub-tests.
• Avoid allocating test name strings entirely by matching directly against the values in the raw file (which will never include escaped characters).

[mukilan]

I agree, rewriting in Rust makes sense. Originally we were planning to have the dashboard show the scores for just 1 year, with a fresh graph for each year like the interop dashboard, but now that we have a single graph, there is a lot of data to process.

Another option is to truncate and archive data beyond a cutoff date (which is what I do when testing changes locally).

[mukilan]

Also, at some point we'll be dropping the data for Layout 2013.

[mrego]

We could also split the chart and only show 2024 (or only show the last 12 months) in the main view wpt.servo.org. We could even keep for future reference something like wpt.servo.org/2023 or whatever with the old data. If that helps to alleviate things and it's not too complex to implement.