gpg: Simplify command --gen-key and add --full-gen-key.
* g10/gpg.c (aFullKeygen): New. (opts): Add command --full-key-gen. (main): Implement it. * g10/keygen.c (DEFAULT_STD_ALGO): Replace wrong GCRY_PK_RSA although the value is identical. (DEFAULT_STD_CURVE): New. (DEFAULT_STD_SUBALGO): New. (DEFAULT_STD_SUBKEYSIZE): New. (DEFAULT_STD_SUBCURVE): New. (quick_generate_keypair): Use new macros here. (generate_keypair): Add arg "full" and fix call callers. Do not ask for keysize in non-full node. (ask_user_id): Add arg "full" and simplify for non-full mode.