Bandersnatch VRF (#14412)

* Introduce bandersnatch vrf

* Some documentation

* Fix tests

* Fix docs refs

* Some more docs

* Comments about key derivation

* Make clippy happy

* Fix ring context enc/dec test

* Fix docs

* Switch to upstream ring-vrf

* Use sub-domains to construct VrfInput

* Bandersnatch VRF experimental feature

* Restore upstream dep

* Fix feature flags

* Apply typo fix

Co-authored-by: Anton <anton.kalyaev@gmail.com>

* Bump bandersnatch-vrfs

* Weiestrass form has been selected

* Rename bandersnatch testing app crypto id

* Support for seed recovery

* Clarified domain size <-> key size relationship

* cargo fmt

* Trigger CI

* Some required tweaks to crypto types

* Remove leftovers from Cargo.toml

* Remove some TODO notes

* Simplification of structs construction

* Trigger CI

* Apply review suggestion

Co-authored-by: Koute <koute@users.noreply.github.com>

* Docs typo

* Fix keystore tests

* Consistence

* Add ref to git rependency

* Static check of MAX_VRF_IOS value

* Clarify behavior for out of ring keys signatures

* Add test for ring-vrf to the keystore

* Fix docs

---------

Co-authored-by: Anton <anton.kalyaev@gmail.com>
Co-authored-by: Koute <koute@users.noreply.github.com>

substrate/primitives/core/src/crypto.rs

@@ -15,9 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// tag::description[]
 //! Cryptographic utilities.
-// end::description[]
 
 use crate::{ed25519, sr25519};
 #[cfg(feature = "std")]
@@ -486,7 +484,7 @@ pub trait ByteArray: AsRef<[u8]> + AsMut<[u8]> + for<'a> TryFrom<&'a [u8], Error
 }
 
 /// Trait suitable for typical cryptographic key public type.
-pub trait Public: CryptoType + ByteArray + Derive + PartialEq + Eq + Clone + Send {}
+pub trait Public: CryptoType + ByteArray + Derive + PartialEq + Eq + Clone + Send + Sync {}
 
 /// An opaque 32-byte cryptographic identifier.
 #[derive(Clone, Eq, PartialEq, Ord, PartialOrd, Encode, Decode, MaxEncodedLen, TypeInfo)]