Allow 2FA to use Email Only

We host systems that are used by customers who change companies all the time. Sometimes when they leave companies, we are not notified. Since people now take their BYOD phones with them, any MFA/2FA using SMS or Authenticator Apps can be used outside their company. This makes Domino's 2FA a security risk for us.

Since most companies cut off access to email upon termination, having 2FA able to be set to "ONLY Via Email" means that we can prevent users from starting at a new company and using their existing logins to our Domino platform to access data that is relevant to their old company.