Tracking issue: Refactor site deployment

[Marigold]

Our deployment process is unnecessarily complex right now. We haven't changed it when migrating from Netlify to Cloudflare and there easy ways how to simplify it:

• [ ] Our site is built into ~/live-data/bakedSite, it could be just ~/bakedSite
• [ ] Deploy scripts are in owid-grapher repo, but it'd be more natural to have them in ops (since they are similar to staging servers)
• [ ] Is the 20000 file limit by Cloudflare still relevant (as a workaround we serve those files from R2)? There's grapher/exports that contains ~9000 files which can make it impossible