db: add different storages

[loup-brun]

Currently, the meets are stored in a JS file src/lib/db.js. This works fine, but lacks type-checking and other features (like ID uniqueness). It's also slightly irritating to open a JS file just to update a meet info. This could be eased by using a live backend database or CMS with a simple web frontend.

Ideas for the meets DB:

• JSON (local file, updated via CMS, such as TinaCMS or FrontAid)
• 3rd-party DB with built-in API (Baserow, Airtable, Supabase Directus, Prismic, etc.)

Each instance would have its own DB configuration (could be file-based for a small instance, web-based DB for larger instances).

TODO extract DB modeling from src/lib/db.js and make a nice table with documentation describing the fields and their usage.

Storages

• file (JSON) - Feat db baserow #27
• Baserow - Feat db baserow #27
• Airtable - db backend: Airtable #29
• Supabase
• Prismic