Limit tiering support

[andyleiserson]

Related Firefox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1979753

To make it harder to use WebGPU for fingerprinting, we want to report limit values that are quantized to a set of pre-defined buckets, rather than raw limit values that are likely to have more entropy that is useful for fingerprinting.

This change implements tiered limit support. Tiered limits are requested by a new apply_limit_tiers flag in RequestAdapterOptions. By default that flag is false and limits are not modified by the tiering logic.

There is a module comment in the new wgpu_core::limits module that explains limit tiering in more depth.

I determined the tiers by crunching a bunch of data from gpuinfo and collected at https://webgpu-limits.netlify.app/. I am not sure how best to capture/preserve the analysis tooling for future use, I'm open to suggestions. For more detail of the tiers, see the tiers.html attachment on the linked bug.

Testing
Adds a directed test suite.

Squash or Rebase? Rebase

Checklist

• Need to change log::info! to debug!.
• Needs a CHANGELOG.md entry.