Show all loaded applications in recordings panel

[emilk]

• Closes Make App ID selectable #5672
• Closes Opening a blueprint appears to do nothing if you have no rrd files #5694

What

• Show all loaded applications in the recordings panel
  • Even those with no recordings
  • Even welcome screen
• Close application when last recording of that app is closed
• Add button to close all recordings in an application
• Make applications selectable
• When loading a blueprint, switch to its application

Being able to quickly select the welcome screen is super useful while exploring examples, and for testing.
It is also the natural place to return to to find the links to the docs, and maybe more stuff in the future.

Demo

At the start here I have pulled in a blueprint for arkit, but no recording for it

show-welcome-screen-in-blueprint-panel-2.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: rerun.io/viewer
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• 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!

• PR Build Summary
• Docs preview
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• Recent benchmark results
• Wasm size tracking

[nikolausWest]

First off I think the whole experience is so much better than before!

I don't like having the welcome screen permanently in the recordings list but feel like it's worth it to try it out with one of the following modifications:

Easiest

Add an option to the options menu to exclude the welcome screen from the recordings list.

Best

Make it possible to remove the welcome screen as well (feels alot more like VSCode. If all recordings are removed, have an empty screen with a very subtle button to load the welcome screen + add an action to the command palette & menu to bring it back. Browny points for making it blueprint configurable to include at all.

[jleibs]

Would be nice to have the blueprints here as well.

[emilk]

Maybe, but could also be very confusing. Do we show all the blueprints? Or just the active and default ones? What if the active and default are the same? Etc. I opted to keep it simple for now.