Show history graphs on performance page

[axel-h]

Now that the performance page is updated regularly, it would be nice to have a graph available that shows the history of each value and link to the commit that was used to build the images that produces these.

[lsf37]

Yes, that would be very nice.

@wom-bat we had something like that on the TV screen -- do you know where the code for it is?

This means we probably need to resurrect a database of performance results. Although for just the graph, we probably only need a file somewhere with data for the last 10 or 20 or so, which could be done directly from the test driver.

Not every commit has performance data available, but those that do could go into the graph and have links back. Images are kept for 3 months, which should be sufficient; the source manifests are in version control and should be available indefinitely.

[axel-h]

loosely related to

• report benchmarking regressions ci-actions#76