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

crypto/frost/src/tests/literal/ed448.rs

@@ -1,8 +1,11 @@
 use rand_core::OsRng;
 
+use ciphersuite::Ciphersuite;
+
+use schnorr::SchnorrSignature;
+
 use crate::{
-  curve::{Curve, Ed448, Ietf8032Ed448Hram, IetfEd448Hram},
-  schnorr::{SchnorrSignature, verify},
+  curve::{Ed448, Ietf8032Ed448Hram, IetfEd448Hram},
   tests::vectors::{Vectors, test_with_vectors},
 };
 
@@ -37,11 +40,9 @@ fn ed448_8032_vector() {
   let R = Ed448::read_G::<&[u8]>(&mut sig.as_ref()).unwrap();
   let s = Ed448::read_F::<&[u8]>(&mut &sig[57 ..]).unwrap();
 
-  assert!(verify(
-    A,
-    Ietf8032Ed448Hram::hram(&context, &R, &A, &msg),
-    &SchnorrSignature::<Ed448> { R, s }
-  ));
+  assert!(
+    SchnorrSignature::<Ed448> { R, s }.verify(A, Ietf8032Ed448Hram::hram(&context, &R, &A, &msg))
+  );
 }
 
 #[test]