gpg: Support encryption with kyber_cv448.
* g10/pkglue.c (do_encrypt_kem): Support cv25519 w/o 0x40 prefix. Support X448. (ECC_POINT_LEN_MAX): New. (ECC_HASH_LEN_MAX): New. * common/openpgp-oid.c (oidtable): Support X448 KEM.
This needs more work. For example we should use a parameter table
like what we do in agent/pkdecrypt.c.
- GnuPG-bug-id: T6815