gpg: Add magic parameter "default" to --quick-add-adsk.

* g10/getkey.c (has_key_with_fingerprint): New.
* g10/keyedit.c (menu_addadsk): Replace code by new function.
(keyedit_quick_addadsk): Handle magic arg "default".
* g10/keygen.c (append_all_default_adsks): New.
--

GnuPG-bug-id: 6882
(cherry picked from commit 77afc9ee1c)

g10/keydb.h

@@ -485,6 +485,10 @@ int parse_auto_key_locate(const char *options);
 int parse_key_origin (char *string);
 const char *key_origin_string (int origin);
 
+/* Return an error if KEYBLOCK has a primary or subkey with the fpr.  */
+gpg_error_t has_key_with_fingerprint (kbnode_t keyblock,
+                                      const byte *fpr, size_t fprlen);
+
 /*-- keyid.c --*/
 int pubkey_letter( int algo );
 char *pubkey_string (PKT_public_key *pk, char *buffer, size_t bufsize);