web: add new email address for user
web: redirect to preview email confirm page when password is invalid
web: show error message when password is invalid
web: fix typo
web: show error page if email address already exists
web: show error message if JWT token is invalid
web: Fix HTML for email field
web: relocate code
web: fix indentation
web: send confirm message when user add new email address
web: puavo needs jwt library (email confirm)
web: use form params