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/test/java/org/elasticsearch/xpack/security/cli/AutoConfigureNodeTests.java
final List<String> file2 = List.of(
            "# commented out line",
            "# commented out line",
            "# commented out line",
            "# commented out line",
            "# commented out line",
            "# commented out line",
            "some.setting1: some.value",
            "some.setting2: some.value",
            "some.setting3: some.value",
            "some.setting4: some.value",
            "# commented out line",
            "# commented out line",
            "# commented out line",
            AutoConfigureNode.AUTO_CONFIGURATION_START_MARKER,
            "cluster.initial_master_nodes: [\"node1\"]",
            "http.host: [_site_]",
            "xpack.security.enabled: true",
            "xpack.security.enrollment.enabled: true",
            "xpack.security.http.ssl.enabled: true",
            "xpack.security.http.ssl.keystore.path: /path/to/the/file",
            "xpack.security.transport.ssl.keystore.path: /path/to/the/file",
            "xpack.security.transport.ssl.truststore.path: /path/to/the/file",
            AutoConfigureNode.AUTO_CONFIGURATION_END_MARKER
        );
        assertEquals(file1, removePreviousAutoconfiguration(file2));
    }
    public void testRemovePreviousAutoconfigurationRetainsUserAdded() throws Exception {
        final List<String> file1 = List.of(
            "# commented out line",