YouTube OAuth2 flow

[evan10s]

• Only need to support one account
• Update README with info on where client_secrets.json should go
• Add https://www.npmjs.com/package/@googleapis/youtube for the YouTube API. Note that you also need to add for the types related to auth (https://www.npmjs.com/package/google-auth-library)

Sample flow:

• Pick somewhere on disk to store the access/refresh tokens for Google (since we aren't doing central auth)
• Add a function that can identify if the auth credentials are present or not (both client_secrets.json and access/refresh token)
  • You will want to add:
  • A function for the frontend that indicates the status of YouTube auth (none, client_secrets.json exists, everything exists)
  • An Express middleware function for API endpoints that require the YouTube auth to be present. Or maybe just a plain function.
• Add a stub method initializing a YouTube API client with the client ID/secret and access/refresh tokens so that it can authenticate with YouTube.

There's no need for frontend work with this - #4 and #8 should cover that.