Smash the singular Ciphersuite trait into multiple

This helps identify where the various functionalities are used, or rather, not
used. The `Ciphersuite` trait present in `patches/ciphersuite`, facilitating
the entire FCMP++ tree, only requires the markers _and_ canonical point
decoding. I've opened a PR to upstream such a trait into `group`
(https://github.com/zkcrypto/group/pull/68).

`WrappedGroup` is still justified for as long as `Group::generator` exists.
Moving `::generator()` to its own trait, on an independent structure (upstream)
would be massively appreciated. @tarcieri also wanted to update from
`fn generator()` to `const GENERATOR`, which would encourage further discussion
on https://github.com/zkcrypto/group/issues/32 and
https://github.com/zkcrypto/group/issues/45, which have been stagnant.

The `Id` trait is occasionally used yet really should be first off the chopping
block.

Finally, `WithPreferredHash` is only actually used around a third of the time,
which more than justifies it being a separate trait.

---

Updates `dalek_ff_group::Scalar` to directly re-export
`curve25519_dalek::Scalar`, as without issue. `dalek_ff_group::RistrettoPoint`
also could be replaced with an export of `curve25519_dalek::RistrettoPoint`,
yet the coordinator relies on how we implemented `Hash` on it for the hell of
it so it isn't worth it at this time. `dalek_ff_group::EdwardsPoint` can't be
replaced for an re-export of `curve25519_dalek::SubgroupPoint` as it doesn't
implement `zeroize`, `subtle` traits within a released, non-yanked version.
Relevance to https://github.com/serai-dex/serai/issues/201 and
https://github.com/dalek-cryptography/curve25519-dalek/issues/811#issuecomment-3247732746.

Also updates the `Ristretto` ciphersuite to prefer `Blake2b-512` over
`SHA2-512`. In order to maintain compliance with FROST's IETF standard,
`modular-frost` defines its own ciphersuite for Ristretto which still uses
`SHA2-512`.

crypto/frost/src/curve/mod.rs

@@ -6,21 +6,16 @@ use rand_core::{RngCore, CryptoRng};
 use zeroize::{Zeroize, Zeroizing};
 use subtle::ConstantTimeEq;
 
-pub use ciphersuite::{
-  digest::Digest,
-  group::{
-    ff::{Field, PrimeField},
-    Group,
-  },
-  Ciphersuite,
+use ciphersuite::group::{
+  ff::{Field, PrimeField},
+  Group,
 };
+pub use ciphersuite::{digest::Digest, WrappedGroup, GroupIo, Ciphersuite};
 
 #[cfg(any(feature = "ristretto", feature = "ed25519"))]
 mod dalek;
-#[cfg(feature = "ristretto")]
-pub use dalek::{Ristretto, IetfRistrettoHram};
-#[cfg(feature = "ed25519")]
-pub use dalek::{Ed25519, IetfEd25519Hram};
+#[cfg(any(feature = "ristretto", feature = "ed25519"))]
+pub use dalek::*;
 
 #[cfg(any(feature = "secp256k1", feature = "p256"))]
 mod kp256;
@@ -38,11 +33,11 @@ pub(crate) use ed448::Ietf8032Ed448Hram;
 
 /// FROST Ciphersuite.
 ///
-/// This exclude the signing algorithm specific H2, making this solely the curve, its associated
+/// This excludes the signing algorithm specific H2, making this solely the curve, its associated
 /// hash function, and the functions derived from it.
-pub trait Curve: Ciphersuite {
+pub trait Curve: GroupIo + Ciphersuite {
   /// Context string for this curve.
-  const CONTEXT: &'static [u8];
+  const CONTEXT: &[u8];
 
   /// Hash the given dst and data to a byte vector. Used to instantiate H4 and H5.
   fn hash(dst: &[u8], data: &[u8]) -> impl AsRef<[u8]> {
@@ -121,7 +116,7 @@ pub trait Curve: Ciphersuite {
   /// Read a point from a reader, rejecting identity.
   #[allow(non_snake_case)]
   fn read_G<R: Read>(reader: &mut R) -> io::Result<Self::G> {
-    let res = <Self as Ciphersuite>::read_G(reader)?;
+    let res = <Self as GroupIo>::read_G(reader)?;
     if res.is_identity().into() {
       Err(io::Error::other("identity point"))?;
     }