Update web viewer links

[jprochazk]

What

Update most web viewer links from app.rerun.io to rerun.io/viewer.

• Part of https://github.com/rerun-io/landing/issues/730

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: app.rerun.io
  • Using examples from latest main build: app.rerun.io
  • Using full set of examples from nightly build: app.rerun.io
• 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
• Examples preview
• Recent benchmark results
• Wasm size tracking

[emilk]

"most"? Which ones aren't updated, and why?

[jprochazk]

Which ones aren't updated, and why?

One example is the example_manifest.json links. There's a difference between "link to the web viewer" and "link to the website that hosts web viewer assets". The latter is staying as app.rerun.io, because we have no way of hosting those assets at rerun.io/viewer or similar.

[jprochazk]

Preview: https://landing-git-jan-viewer-migration-rerun.vercel.app/viewer/pr/5738?manifest_url=https%3A%2F%2Fapp.rerun.io%2Fversion%2Fnightly%2Fexamples_manifest.json