[Tech] Server-side Auth

[mariojsnunes]

Is your feature request related to a problem? Please describe.
We want Server-side Auth to improve the platform security.
By having it, we can migrate some of our code to APIs which improves the platform maintainability.

To to this with firebase, the Admin SDK must be used.
For the Admin SDK to work we need it's service account private key.
For local development, all contributors would need the private key.

Options:

1. We could commit it to the repo, the dev database is open anyway.
2. Development with the emulator would be a requirement.
3. Do not create APIs that require auth now, wait for Supabase.
   1. On Supabase, there won't be a shared database, everyone would use their local one.