Passkeys now available for passwordless sign-in and 2FA on GitLab

Introduces passkeys as a new authentication method for passwordless sign-in and as a phishing-resistant 2FA option. Passkeys leverage WebAuthn and public-key cryptography, with private keys stored on the device and public keys on GitLab. They are supported across various browsers, mobile devices, and hardware security keys. This aligns with the CISA Secure by Design Pledge to increase MFA usage.