gpg: Switch to ed25519+cv25519 as default algo.
* g10/keygen.c (DEFAULT_STD_KEY_PARAM): Change to former future default ago. (ask_algo): Change default and also the way we indicate the default algo in the list of algos. (ask_curve): Indicate the default curve.
- Signed-off-by: Werner Koch <wk@gnupg.org>