Implement a "benchmark producer" server #124
Description
The LNT server contains data that allows it to detect regressions. However, it might not contain performance data for every single commit (e.g. if we run benchmarks on a nightly basis). It would be great if the server could somehow communicate back with the builders to request benchmark data for other commits, allowing the performance regression to be bisected to a specific commit. This could also potentially be used to decrease noise by requesting additional runs for orders where the data appears to be noisy.