E-mail verification

[bktiel]

Add another layer of security to the platform by verifying *.westpoint.edu email addresses

Goals:

1. Add field to User definition: Users are either "verified" or "unverified."
2. Unverified Users do NOT have access to Helios; instead they will be asked for their westpoint.edu email.
3. An email is sent to the address with a unique verification URL. Once this URL is served, the account is marked 'verified' and the user has access to Helios
4. This should also serve as an automated method for promoting users within Discord. Discord should prompt new users to verify on Helios for more access. Once they are verified, they will receive the "Cadets" role that gives access to the broader Discord. Faculty should remain verified 'on-request' as there is no way to discriminate status based on email without keeping a running list (cumbersome).