New -encopt option for pkey(1) and genpkey(1)

New -encopt option for pkey(1) and genpkey(1)

This allows setting the ML-KEM and ML-DSA output formats.
At the same fixing surprising lack of password encryption
of PKCS#8 private keys in DER output form in the CLI apps.

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Nikola Pajkovsky <nikolap@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/29324)