Fix password prompt for pki CLI

The pki CLI has been modified to disable ConsolePasswordCallback if
the password config is specified (e.g. during installation). In
other cases it will allow ConsolePasswordCallback to be used by NSS
to request additional passwords from the user.

The pki nss-key-del has been added to remove a key.

The CryptoUtil.deletePrivateKey() has been updated to remove the
public key associated to the private key being removed if exists.

The tests for pki CLI with RSA, ECC, and SoftHSM has been updated
to create CA signing cert, SSL server cert, and audit signing cert
to validate the password prompts.

Author: edewata