scd:piv: Support listing of retired keys with KEYINFO.
* scd/app-piv.c (data_objects): Mark returned key as having a keypair. (do_with_keygrip): Check against encrusage and not used one tag. * tools/gpg-card.c (piv_keyref_is_retired): New. (list_all_kinfo): Pretty print retired keys.
This allows to list all existing retired keys without using separate
readkey commands.