Fix pkeyutl/rsautl empty encrypt-input/decrypt-output handling

Also fix option processing in pkeyutl to allow use of (formerly)
"out-of-order" switches that were needless implementation limitations.

Handle documented "ENGINE" form with -keyform and -peerform.

Better handling of OPENSSL_NO_ENGINE and OPENSSL_NO_RSA.

RT2018

Reviewed-by: Rich Salz <rsalz@openssl.org>