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/HttpCertificateCommand.java
);
                    } else {
                        
                        return FileType.PEM_CERT_CHAIN;
                    }
            }
        } catch (UncheckedIOException | IOException e) {
            terminal.errorPrintln("Cannot determine the file type for " + path);
            terminal.errorPrintln(e.toString());
            return FileType.UNRECOGNIZED;
        }
        return FileType.UNRECOGNIZED;
    }
    private void printHeader(String text, Terminal terminal) {
        terminal.println("");
        terminal.println(Terminal.Verbosity.SILENT, "## " + text);
        terminal.println("");
    }
    /**
     * The standard zip output stream cannot be wrapped safely in another stream, because its close method closes the
     * zip file, not just the entry.
     * This class handles close correctly for a single entry
     */
    private class ZipEntryStream extends OutputStream {
        private final ZipOutputStream zip;
        ZipEntryStream(ZipOutputStream zip, String name) throws IOException {
            this(zip, new ZipEntry(name));
        }
        ZipEntryStream(ZipOutputStream zip, ZipEntry entry) throws IOException {
            this.zip = zip;