Update backend and full-stack hiring processes
Created by: tsenart
This commit updates the hiring processes for backend and full stack roles.
Notable changes:
- Coding exercise for full stack comes after first 30 minute call with the candidate, instead of directly scheduling a call with the hiring manager.
- Coding exercise reviewers are chosen each time by the hiring manager of the team the candidate expressed preference for.
- Interviewer roster change for the Architecture interview.