Smash Ciphersuite definitions into their own crates

Uses dalek-ff-group for Ed25519 and Ristretto. Uses minimal-ed448 for Ed448.
Adds ciphersuite-kp256 for Secp256k1 and P-256.

crypto/dalek-ff-group/src/lib.rs

@@ -38,6 +38,9 @@ use group::{
 mod field;
 pub use field::FieldElement;
 
+mod ciphersuite;
+pub use crate::ciphersuite::{Ed25519, Ristretto};
+
 // Use black_box when possible
 #[rustversion::since(1.66)]
 mod black_box {