Create a dedicated crate for the DKG (#141)

* Add dkg crate

* Remove F_len and G_len

They're generally no longer used.

* Replace hash_to_vec with a provided method around associated type H: Digest

Part of trying to minimize this trait so it can be moved elsewhere. Vec, 
which isn't std, may have been a blocker.

* Encrypt secret shares within the FROST library

Reduces requirements on callers in order to be correct.

* Update usage of Zeroize within FROST

* Inline functions in key_gen

There was no reason to have them separated as they were. sign probably 
has the same statement available, yet that isn't the focus right now.

* Add a ciphersuite package which provides hash_to_F

* Set the Ciphersuite version to something valid

* Have ed448 export Scalar/FieldElement/Point at the top level

* Move FROST over to Ciphersuite

* Correct usage of ff in ciphersuite

* Correct documentation handling

* Move Schnorr signatures to their own crate

* Remove unused feature from schnorr

* Fix Schnorr tests

* Split DKG into a separate crate

* Add serialize to Commitments and SecretShare

Helper for buf = vec![]; .write(buf).unwrap(); buf

* Move FROST over to the new dkg crate

* Update Monero lib to latest FROST

* Correct ethereum's usage of features

* Add serialize to GeneratorProof

* Add serialize helper function to FROST

* Rename AddendumSerialize to WriteAddendum

* Update processor

* Slight fix to processor

processor/src/coin/monero.rs

@@ -4,7 +4,7 @@ use curve25519_dalek::scalar::Scalar;
 
 use dalek_ff_group as dfg;
 use transcript::RecommendedTranscript;
-use frost::{curve::Ed25519, FrostKeys};
+use frost::{curve::Ed25519, ThresholdKeys};
 
 use monero_serai::{
   transaction::Transaction,
@@ -55,7 +55,7 @@ impl OutputTrait for Output {
 
 #[derive(Debug)]
 pub struct SignableTransaction {
-  keys: FrostKeys<Ed25519>,
+  keys: ThresholdKeys<Ed25519>,
   transcript: RecommendedTranscript,
   // Monero height, defined as the length of the chain
   height: usize,
@@ -157,7 +157,7 @@ impl Coin for Monero {
 
   async fn prepare_send(
     &self,
-    keys: FrostKeys<Ed25519>,
+    keys: ThresholdKeys<Ed25519>,
     transcript: RecommendedTranscript,
     block_number: usize,
     mut inputs: Vec<Output>,