apps/pkcs12: print multiple PKCS#12 safeBag attribute values if present

apps/pkcs12: print multiple PKCS#12 safeBag attribute values if present

Currently the pkcs12 app will only ever print the first value of a multi-value
attribute. This is OK for some attributes (e.g. friendlyName, localKeyId) but
may miss values for other attributes.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/9751)

(cherry picked from commit dbcc7b45670483cc89428afe1d3c363ef83d76df)