Enable selecting data sources and blueprints and recordings in them

[emilk]

What

• Part of Improve default selection panel #5645

If you click a recording you will now see what blueprints are in the same data source.
You can also select the data source directly to see all recordings and blueprints in it.
Selecting a blueprint is now also possible.
I also added the size of the store to the selection panel.

select-data-source.mp4

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using newly built examples: app.rerun.io
  • Using examples from latest main build: app.rerun.io
  • Using full set of examples from nightly build: app.rerun.io
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!

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[github-actions]

Size changes

Name	main	5646/merge	Change
rrt-star.rrd	2.24 MiB	11.60 MiB	+417.86%

[Wumpf]

Nice!!
I'm still pondering if some of this should go behind a feature flag to protect users from strange / undocumented behavior, but I'm leaning more and more towards this being a net improvent regardless and that there's no point in gating it.

The very unrelated default legend needs fixing / roll-back