feat: registration & login with code

[Benehiko]

Related Issue or Design Document

Adds support for the UserAuthCard to handle registration and login with the code method.

Checklist

• [ ] I have read the contributing guidelines and signed the CLA.
• [ ] I have referenced an issue containing the design document if my change introduces a new feature.
• [ ] I have read the security policy.
• [ ] I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security vulnerability, I confirm that I got green light (please contact security@ory.sh) from the maintainers to push the changes.
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [ ] I have added necessary documentation within the code base (if appropriate).

Further comments

[Benehiko]

I still need to do the settings flow and maybe a couple more tests (e2e mocks on the examples). But it's quite far already.