Add -force_pubkey -multivalue-rdn -set_issuer -set_subject -utf8 to x509 app

Add -force_pubkey -multivalue-rdn -set_issuer -set_subject -utf8 to x509 app

The -set_issuer, -set_subject, and -force_pubkey features can be used to
'rechain' PKIs, for more information see https://labs.apnic.net/nro-ta/
and https://blog.apnic.net/2023/12/14/models-of-trust-for-the-rpki/

OK tb@