Session fixation attacks were prevented because a session ID was
regenerated at each first factor authentication but this commit
generalize session regeneration from first to second factor too.
Fixes#180
* Remove unused mongo docker-compose file.
* Default redirection URL was not taken into account.
* Fix possible storage options in config template.
* Remove useless checks in u2f registration endpoints.
* Add default redirection url in config of duo suite.
* Fix log line in response handler of 2FA methods.
* Fix integration tests.
Co-authored-by: Amir Zarrinkafsh <nightah@me.com>