We generate certificates that are intended to be used for server authentication in a couple of places:

- `bin/elasticsearch-certutil http` command  ( See `CertGenUtils.generateSignedCertificate` in `HttpCertificateCommand` )
- TLS auto-configuraion for node startup ( see [`AutoConfigureNode`](https://github.com/elastic/elasticsearch/blob/814f7f9f52cb8c05db6465b9bfc818ea5d76c575/x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/AutoConfigureNode.java#L454) )

In these cases we know that the certificate is meant to be used for server authentication, so we can set Extended Key Usage extension to `1.3.6.1.5.5.7.3.1`
x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/AutoConfigureNode.java
Terminal.Verbosity.VERBOSE,
                ExitCodes.NOOP,
                "Skipping security auto configuration because it appears that security is already configured."
            );
        }
        
        if (false == settings.getByPrefix(XPackSettings.TRANSPORT_SSL_PREFIX).isEmpty()
            || false == settings.getByPrefix(XPackSettings.HTTP_SSL_PREFIX).isEmpty()) {
            
            notifyOfFailure(
                inEnrollmentMode,
                terminal,
                Terminal.Verbosity.VERBOSE,
                ExitCodes.NOOP,
                "Skipping security auto configuration because it appears that TLS is already configured."
            );
        }
        
        
        if (false == isInitialClusterNode(settings)) {
            notifyOfFailure(
                inEnrollmentMode,
                terminal,
                Terminal.Verbosity.VERBOSE,
                ExitCodes.NOOP,
                "Skipping security auto configuration because this node is configured to bootstrap or to join a "
                    + "multi-node cluster, which is not supported."
            );
        }
        if (inEnrollmentMode == false) {