Automatically synchronize build.rerun.io & release assets

[teh-cmc]

This introduces new scripts and workflows to synchronize the contents of our cloud storage (build.rerun.io) with our release assets.

This can either be run manually from a dev machine, e.g.:

python scripts/ci/sync_release_assets.py --github-release prerelease --github-token <GITHUB_TOKEN> --remove --update

or manually dispatched through the Actions interface, e.g. here.

It will run automatically as part of the pre-release process on push-to-main.

---

Here's how that looks today:

---

• Part of Tracking issue: binary assets for everyone and everything #3942
• Fixes Set up rerun binary release artifacts #2107

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 demo.rerun.io (if applicable)
• 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