Secure user registration

### Background on the problem the feature will solve/improved user experience
Users of the application will be required to log-in ahead of accessing the application's capabilities.

### Describe the solution you'd like
As an upstander / contacted person I can securely register for the platform, knowing my identity will be privacy protected.

### Tasks

- [ ] create authentication protocol
- [ ] investigate IBM AppID
- [ ] create authorization protocol
- [ ] User journey/Technical requirements session

_TBD_

### Technical requirements
- Registration DB
- Password protection (MFA)
- SSO (?)

### Roles Required
- React
- React Native
- User authorisation (e.g. https://auth0.com/blog/complete-guide-to-react-user-authentication/)

### Acceptance Criteria
- A user can sign up with an email address or social log in
- They are able to set a password for their account use
- They are able to retrieve their email, username, or password if forgotten

Es werden keine Implementierungsdateien oder Tests genannt. Beginne mit der Prüfung der Registrierungsanforderungen und des verlinkten Auth0-Leitfadens und untersuche anschließend IBM AppID; definiere die Authentifizierungs- und Autorisierungsprotokolle, die Registrierungsdatenbank, den Passwortschutz/MFA, SSO und den Wiederherstellungsablauf, bevor du die Akzeptanzkriterien überprüfst.

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