Allow multiple emails to be associated with a WCA account

[khkellis]

Is your feature request related to a problem? Please describe. There are common occurrences, especially with new and young competitors, who sign up for an account with their personal email, despite their parent being the one primarily communicating with competition organizers. Uncertainties about registration, updates about competition schedules, etc. get sent to the competitor's email. The updates are then not accounted for by the parent/guardian, which can cause problems such as a competitor spending money to a competition they didn't actually successfully register for.

Describe the solution you'd like Allow multiple emails to be associated with a single account. All communication from the WCA site would be sent to all emails associated with the account.

Describe alternatives you've considered N/A

Additional context Ed Hollingdale also had alternative reasons: "Back in Australia I would want my personal email to be used for when I sign up to a random comp, my Speedcubing Australia email to be used for all organiser[sic] matters, and my WCA email to be used for delegate related matters."

[dunkOnIT]

This + the additional context start to suggest some requirements for a User rework:

• Allow a user to have multiple roles, and optionally associate a different email with each role
• Create some sort of family/parent-or-guardian associations for the accounts of minors, such that communication could be directed either to the competitor alone, or to the parent/guardian, or to both