Fetch GitHub projects at build-time

[gomorizsolt]

There are two recurring issues with fetching the projects at client-side (i.e. after the project has rehydrated):

• the request quota can be exceeded fairly simply (60 / hour if they're unauthenticated)
• CORS errors (not sure of why it happens though)

As discussed, one solution to circumvent these issues would be to fetch at build-time.

See: https://nextjs.org/docs/basic-features/data-fetching#getstaticprops-static-generation

This implies we should take care of stale data (e.g. schedule a daily rebuild).