Prepare website for first AU4 alpha

[LWinterberg]

• made a new page, /au4, for the first audacity 4 alpha
• also refactored releasedata into separate files
• also updated astro
• also made it so openvino only checks minor version compatibility (so the page won't fall out of date as quickly

[netlify]

✅ Deploy Preview for audacityteam ready!

Name	Link
🔨 Latest commit	e326cc6
🔍 Latest deploy log	https://app.netlify.com/projects/audacityteam/deploys/68dff1bc52e3ee00087da0b5
😎 Deploy Preview	https://deploy-preview-63--audacityteam.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 98 (no change from production) Accessibility: 98 (no change from production) Best Practices: 100 (🟢 up 8 from production) SEO: 100 (no change from production) PWA: - View the detailed breakdown and full score reports

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[teetow]

LGTM!

[DilsonsPickles]

Some grammatical fixes:

"We expect the following flow to work reasonably well:"

I'd update this to "following flows..."

Remove all full stops (periods) from list items

For concrete and reproducible bugs only: Github issues

Perhaps change this to: Github issues (For concrete and reproducible bugs only)