UI to show multiple stats for other users

**Is your feature request related to a problem? Please describe.**
I'd like to be able to see mean / ao5 / ao12 / etc... for other users at the same time

**Describe the solution you'd like**
One option is to press the "mean" button to cycle between the stats. This won't be obvious to most users however.

Another option is to press mean and it toggles more rows showing in the header with the various stats (if enough solves exist for any user)

Another option is to add a whole other panel and somehow toggle between viewing it.

Start by locating the UI that shows the mean button and per-user stats in the header. Review how existing solve counts and statistics are displayed, then clarify which interaction or panel design should be chosen; done should mean users can view mean, ao5, ao12, and other available stats for multiple users at once.

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