* Add re-auth handler for Picnic
* Extracted authentication part so right form/errors can be shown during re-auth flow
* Add tests for Picnic's re-authentication flow
* Simplify re-auth flow by using the same step as step_user
* Use user step also for re-auth flow instead of having an authenticate step
* Add check for when re-auth is done with different account
* Remove unnecessary else in Picnic config flow
* Fix the step id in the translation strings file
