feat: remove platform attachment requirement on registration

[lfleischmann]

Description

Remove platform attachment requirement on registration and change isUserVerifyingPlatformAuthenticatorAvailable calls to the general Webauthn availability check.

Implementation

Safari currently (v. 16.2) does not provide a UI in case of a (registration) ceremony being performed with an authenticator NOT protected by e.g. a PIN. While Chromium based browsers do offer a UI guiding through the setup of a PIN, Safari simply performs the ceremony without then setting the UV flag even if it is required. On finalization in the backend, this ultimately leads to an error of in the webauthn library which is then "swallowed" by being mapped to a generic error response ("Failed to validate attestation"). In order to provide an appropriate error message to the frontend/user, I had to return an error response distinguishable from other error cases so the webauthn handler now returns an HTTP error with a
dedicated/separate HTTP status code (i.e. NOT "Bad request") because it seemed a bit more robust than forcing the frontend to check on a matching (sub-)string in the error message in order to properly display the error.

Tests

The changes add e2e test runs to check whether WebAuthn credentials now allow for transports other than platform . However, the e2e tests do not test the above mentioned implemented error handling for user verification failures because:

1. The e2e tests only use Chromium, the error handling is more or less a Safari workaround
2. While authenticators used in the virtual WebAuthn environment can be configured to either not have user verification capabilities at all or to simply return a false user verification flag, the WebAuthn API/browser responds with an exception/error, so the authenticator response does not even reach the backend and the above mentioned error handling implementation does not take effect.

How to test

Run the tests or/and run the quickstart.

[FreddyDevelop]

LGTM