Develop background on how user authentification is done in streber.
This issue is really complex because it envolves aspects like:
- Getting the default language for translation as early as possible.
- Avoid cycles between loginForm / loginFormSubmit.
- Support temporary authentification from links in e-mails
- Support of anonymous browing
- Support pages that have to be accessible even if user is not yet authentificated (like License and Login)