Fork macaw as re_math; update glam

[emilk]

What

• Closes Update glam and fork macaw #6467

macaw (which I was one of the main contributors at Embark) is no longer maintained. This is holding us back from updating glam.

macaw was never published as repository anywhere, so I just copied the code from it (it's Apache2/MIT) and modernized it slightly.

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 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!
• If have noted any breaking changes to the log API in CHANGELOG.md and the migration guide

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

To run all checks from main, comment on the PR with @rerun-bot full-check.

[Wumpf]

lgtm but the licensing thing can't be right

There's a bunch of things dragged in here where I'm not sure they're actually needed. But admittedly everything looks very useful to have around.

[Wumpf]

we can't just apply our own license when it's clearly c&p from a different project to which other people contributed

[emilk]

I'll do this in a separate repo instead, with more proper history and licensing info

[emilk]

It's now its own repo instead: https://github.com/rerun-io/re_math

[emilk]

New PR: #6867