Closes #377
https://github.com/rails/rails/pull/23980
- Remove `Que::Mailer` (#895) - Add preview - DRY templates - Add tests - Extract translations
- Extract to Devise custom strategy - Use `SSL_CLIENT_S_DN_CN` env variable instead of `SSL_CLIENT_S_DN` to get ID card data - Remove `database_authenticatable` strategy from `RegistrantUser` Closes #1047