Hashing proc macro utils (#9875)

* hashing macro

* fmt

* use in easy place, and fix blake sizes

* fix

* Fixes, docs.
Allow ident as input.

* fix doc tests

* update error in test (nmapkey and key are same type).

* hashing crates under sp_core

* Doc updates and format.

* use all existing hashing functions.

* return array of u8

* Update primitives/core/hashing/proc-macro/src/impls.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* ToTokeen for an array of u8

* fix

* re

* Improve impls

* complete doc tests

* fmt

* fix doctest format

* fix ui test (nmap key type alias)

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Bastian Köcher <info@kchr.de>

substrate/primitives/core/hashing/Cargo.toml

@@ -0,0 +1,31 @@
+[package]
+name = "sp-core-hashing"
+version = "4.0.0-dev"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+license = "Apache-2.0"
+homepage = "https://substrate.dev"
+repository = "https://github.com/paritytech/substrate/"
+description = "Primitive core crate hashing implementation."
+documentation = "https://docs.rs/sp-core-hashing"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+sp-std = { version = "4.0.0-dev", default-features = false, path = "../../std" }
+byteorder = { version = "1.3.2", default-features = false }
+
+blake2-rfc = { version = "0.2.18", default-features = false }
+tiny-keccak = { version = "2.0.1", features = ["keccak"] }
+sha2 = { version = "0.9.2", default-features = false }
+twox-hash = { version = "1.5.0", default-features = false }
+
+[features]
+default = ["std"]
+std = [
+	"blake2-rfc/std",
+	"sha2/std",
+	"sp-std/std",
+	"twox-hash/std",
+]