Add functions to print an attribute certificate. Several
attribute value types defined by the RFC 5755 specification
are multi-field values (i.e ASN1_SEQUENCE rather than an ASN1_STRING
or similar format). Currently those values are printed using
`ASN1_item_print`. A more user-friendly output mechanism (maybe
similar to the i2r_ functions used for X509 extensions) could be
added in future.
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15857)
