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/schnorr/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "schnorr-signatures"
+version = "0.1.0"
+description = "Minimal Schnorr signatures crate hosting common code"
+license = "MIT"
+repository = "https://github.com/serai-dex/serai/tree/develop/crypto/schnorr"
+authors = ["Luke Parker <lukeparker5132@gmail.com>"]
+keywords = ["schnorr", "ff", "group"]
+edition = "2021"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[dependencies]
+rand_core = "0.6"
+
+zeroize = { version = "1.5", features = ["zeroize_derive"] }
+
+group = "0.12"
+ciphersuite = { path = "../ciphersuite", version = "0.1" }
+
+multiexp = { path = "../multiexp", version = "0.2", features = ["batch"] }
+
+[dev-dependencies]
+dalek-ff-group = { path =  "../dalek-ff-group", version = "^0.1.2" }
+ciphersuite = { path = "../ciphersuite", version = "0.1", features = ["ristretto"] }