Feature/i18n for ticket system

Identity.new.valid? should not crash. So validate presence where needed and
skip the other validations if the value is absent.

We create an identity alongside each user. Make sure the identity
is valid when creating the user. This also ensures that the login
picked is available because otherwise the identities address would
not be available anymore.

hash token with sha512 against timing attacs #3398

We create them. let's reflect that in the verb.

Only storing the date as that should suffice for normal expiry and is less useful for identifying users by timestamps