Reviewer and Tutors can change their passwords

Description / Overview

Provide a standard way of changing and reseting user passwords for tutors and reviewers. Having a way to send passwords via email, or sending emails with auth tokens that enable login or password change would be nice not it is not a priority and requires an smtp server in production (not at all an issue, just bind port 25 into docker container).

Use cases

Tutors and Reviewers only, as Students do not have passwords (See #31 (closed)).

Links / references

Django documentation on passwords

Feature checklist

• Tutors and Reviewers can change their passwords
• Old password has to be entered before change
• User can request that their password may be reset and sent to their (verified) email (optional)