gpg: Implement searching keys via keygrip.
* kbx/keybox-defs.h (struct _keybox_openpgp_key_info): Add field grip. * kbx/keybox-openpgp.c (struct keyparm_s): New. (keygrip_from_keyparm): New. (parse_key): Compute keygrip. * kbx/keybox-search.c (blob_openpgp_has_grip): New. (has_keygrip): Call it.
This has been marked for too long as not yet working. However, it is
a pretty useful feature and will come pretty handy when looking for
all keys matching one keygrip.
Can be optimized a lot by storing the keygrip in the meta data. This
will be done along with the upgrade of KBX for v5 fingerprints.
- Signed-off-by: Werner Koch <email@example.com>