public static List<X509Certificate> fromSlime(Inspector object) {
        return SlimeUtils.entriesStream(object.field(certificateField))
                .map(Inspector::asString)
                .map(X509CertificateUtils::fromPem)
                .toList();
    }
Serializer for operator certificates.
The certificates are serialized as a list of PEM strings.
@author tokle
configserver/src/main/java/com/yahoo/vespa/config/server/tenant/OperatorCertificateSerializer.java