Large backend refactoring, moving away from fbId and uuid dependencies.

- Don't use fbId directly, instead use providerId for maximum compatibility
- Store profile photo URL in user database to support other login providers
- Add provider field in user schema
- Remove use of uuid as user id key, instead use built-in _id
- Refactor and reorganize user creation flow code
- API key support, not yet integrated into frontend

Impacts:
- Many schemas changed. Old statistics will not yet show up until database migrations are written. However, login/search functionality should remain intact.
- Changes support additional login providers in the near future
Multiple provider routing
Twitter and Google login providers support
Merge remote-tracking branch 'origin/feature/no-uuid' into wow-develop

Conflicts:
	app.js
	models/user.js
	routes/auth.js
	views/home.ejs