We want to remove/refactor the whole ModelValidator class as part of the
Doctrine refactor.
This commit moves the method ModelValidator::validateNonRoleEmail() to a
new Validator class as the method is not used by the validator system of
the Paris models. ModelValidator::validateEmail() was also moved as it
is called by ModelValidator::validateNonRoleEmail().
[MAILPOET-4343]
00d021109c