This enables Elasticsearch to use the JVM-wide configured
PKCS#11 token as a keystore or a truststore for its TLS configuration.
The JVM is assumed to be configured accordingly with the appropriate
Security Provider implementation that supports PKCS#11 tokens.
For the PKCS#11 token to be used as a keystore or a truststore for an
SSLConfiguration, the .keystore.type or .truststore.type must be
explicitly set to pkcs11 in the configuration.
The fact that the PKCS#11 token configuration is JVM wide implies that
there is only one available keystore and truststore that can be used by TLS
configurations in Elasticsearch.
The PIN for the PKCS#11 token can be set as a truststore parameter in
Elasticsearch or as a JVM parameter ( -Djavax.net.ssl.trustStorePassword).
The basic goal of enabling PKCS#11 token support is to allow PKCS#11-NSS in
FIPS mode to be used as a FIPS 140-2 enabled Security Provider.