[keycloak-dev] Pull Request #4546: Enable X.509 client certificate user authentication when hosting KC behind a reverse proxy

Hello kc team, This is a request for review & comments. In in the pull request is a refactored implementation of the original X509 client cert user authentication to enable x509 auth when behind a reverse proxy. Let me know whether this is a feature that KC team deems useful. Comments how to improve the implementation are welcome Regards, --Peter