What

• Fixes Parallelize space views #1325

Two levels of parallism actually:

• All context & part systems for a single space view each run in parallel
• All space views now in parallel first setup their query and then kick of their (parallized!) system execution

This gives us major speedups whenever:

• There is several heavy systems in a scene (e.g. a lot of points and a lot of arrows)
• There is several space views

As such this is a very fundamental & widely applicable parallelization!

(a rather silly "points with arrows" scene duplicated a bunch of times. Note that we still don't have any caching, so all these space views might as well be animated individually!)

Related things that are not parallel yet:

• ui methods per space view (run one by one)
• draw call recording (done as part of the ui method, but we could likely do this in parallel, only joining on these tasks when egui wants to queue up the command buffers)
• processing within a system depends on the system at hand. Today, only point cloud has some parallization

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):
  • Full build: app.rerun.io
  • Partial build: app.rerun.io - Useful for quick testing when changes do not affect examples in any way
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG

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

End of a series on refactors leading to this parallization:

• Selection state is now fully double buffered and has interior mutability #4387
• Enable (selected) new cargo clippy lints #4404
• Time control is now behind a RwLock, making recording config access non-mutable everywhere #4389
• Interior mutablilty for re_renderer's static resource pools (RenderPipeline/Shader/Layouts/etc.) #4421
• Make draw data creation no longer require a mutable re_renderer context  #4422
• Make viewer contexts's render context reference non-mutable #4430
• Pass viewer context always non-mutable #4438
• Parallize Space View system evaluation #4460