Multiple email addresses/phone numbers per users.

[evert]

• [x] No longer let clients set the 'active' property when creating users (will default to true)
• [x] Allow some clients to immediately mark an email address as 'verified' during user creation.
• [x] Don't allow users to log in using an identity that's not yet verified.
• [x] Documentation regarding this BC change.
• [x] verification token associated to identities must be verified.