Idea: Shared scale for the page weight plots

[Krinkle]

The lighthouse scores are set to the same 0-400 scale, which makes them visually comparable. I.e. as you scroll down, the far end of the graphs go lower, as it is sorted by score.

The page weight graphs, however, do not share the same scale. This means they all tend to be at the "top" despite being of very different sizes. I suppose there is a benefit to "zooming in" to the relatively change of a given website, but with the kilobyte number as small as it is, the difference is perhaps easier to appreciate if the graphs also shared the same scale. E.g. the top of the page weight scales would be determined by the largest data point within the range of time and sites shown on the current page.

Example from https://www.speedlify.dev/test-runners/: