refac: use dependencies to verify token

- feat: added new util to get the current user when needed. Middleware was adding authentication logic to all the routes. let's revisit if we can move the non-auth endpoints to a separate route.
- refac: update the routes to use new helpers for verification and retrieving user
- chore: added black for local formatting of py code

backend/requirements.txt

@@ -18,3 +18,5 @@ bcrypt
 
 PyJWT
 pyjwt[crypto]
+
+black