Deploy docusaurus docs via GitHub Actions to Cloudflare

[ryscheng]

What is it?

For static sites, I'm looking to move more stuff to Cloudflare.
Partly because Vercel does not support Docker deployments
https://vercel.com/guides/does-vercel-support-docker-deployments

That means that we'll be more limited in what kind of builds we can support (e.g. dbt docs). GitHub actions has no such limitations.

Plus we use Cloudflare for CDN / DNS anyway, so it's one less thing to worry about.

It's also nice in the mono-repo to only deploy on merges to main based on changes to a subdirectory.

[ryscheng]

Testing it out here
#1516

[ryscheng]

Fixed
a bug here #1518

we live!