Create dedicated message structures for FROST messages (#140)

* Create message types for FROST key gen

Taking in reader borrows absolutely wasn't feasible. Now, proper types
which can be read (and then passed directly, without a mutable borrow)
exist for key_gen. sign coming next.

* Move FROST signing to messages, not Readers/Writers/Vec<u8>

Also takes the nonce handling code and makes a dedicated file for it, 
aiming to resolve complex types and make the code more legible by 
replacing its previously inlined state.

* clippy

* Update FROST tests

* read_signature_share

* Update the Monero library to the new FROST packages

* Update processor to latest FROST

* Tweaks to terminology and documentation

crypto/dleq/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "dleq"
-version = "0.1.1"
+version = "0.1.2"
 description = "Implementation of single and cross-curve Discrete Log Equality proofs"
 license = "MIT"
 repository = "https://github.com/serai-dex/serai/tree/develop/crypto/dleq"

crypto/dleq/src/lib.rs

@@ -61,7 +61,7 @@ pub enum DLEqError {
   InvalidProof,
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
 pub struct DLEqProof<G: PrimeGroup> {
   c: G::Scalar,
   s: G::Scalar,