Provide high-level api for key management functions (create, add, edit, import, export, etc) that use underlying gpgme[pp] functions.

API should simplify and abstract high-level functionality instead of providing 1:1 parity with underlying gpgme functions. For example, nodejs gpgKeyImport(...) would be the only function for importing keys while using multiple underlying gpgme[pp] functions:

gpgme_op_import       (... gpgme_data_t keydata) ASCII/binary
gpgme_op_import_keys  (... gpgme_key_t *keys)    in-memory
gpgme_op_receive_keys (... const char *keyids[]) external keyserver, etc