Docusaurus flip

[mike-solomon]

• [x] Update docusaurus.config.ts file with docs.openrewrite.org.
• [x] Update Algolia to either create a new index or point to the new URL. This may involve updating the docusaurus.config.ts file.
• [x] Update CNAME file to point to docs.openrewrite.org
• [x] Update the github pages url: https://github.com/openrewrite/rewrite-docs/settings/pages
• [x] https://github.com/moderneinc/infra/pull/979
• [x] Remove the sync from GitBook so nothing weird happens.
• [x] Updated the pages workflow to detect changes to master instead of docusaurus branch: https://github.com/openrewrite/rewrite-docs/blob/master/.github/workflows/pages.yml#L8
• [x] Updated unneeded recipe changes workflow to detect the new location of the docs (docs/recipes instead of reference/recipes): https://github.com/openrewrite/rewrite-docs/blob/master/.github/workflows/unneeded_recipe_updates.yml
• [x] Merge in Docusaurus markdown generator PR: https://github.com/openrewrite/rewrite-recipe-markdown-generator/pull/136