add referral system

[adityamakkar000]

changes

• add .env and template
• add refferals to user table
• add ability for user to send 10 emails and create shadow accounts + send email (api/register/)

[Yourself1011]

Some changes:

• "referral" is spelled wrong in multiple places
• Use the enum generated by prisma instead of creating your own (LoginResult from @prisma/client instead of InputStatus)
• Try to use server actions instead of API routes when possible (internally it's the same thing, but we get type safety with server actions)
• Use whether the user has been referred to determine if they can refer others, rather than using the preregistration status