Configure Netlify CMS for github integration

[Greenheart]

• [x] Store content as JSON files in a /content sub-directory.
• [x] Update the /cms sub directory to use Netlify CMS (with vite) and delete old code.
• [x] Create the content structure based on current schema.
• [x] Create an ID widget that creates unique ids for content created in the CMS.
• [x] Enable relationships between content pieces.
• [ ] Add GitHub backend with open authoring - allowing people to sign in using their GitHub accounts, and create pull requests from their own forks.
• [ ] Maybe use GitHub GraphQL API for faster performance.
• [x] Maybe support file uploads for images via a public directory. Or use embeds and links.