Support for keyring in runtimes (#2044)

This functionality is required for #1984.

This PR enables
[`sp-keyring`](https://github.com/paritytech/polkadot-sdk/blob/21d36b7b4229c4d5225944f197918cde23fda4ea/substrate/primitives/keyring/src/sr25519.rs#L31-L40)
in `no-std` environments, allowing to generate the public key (e.g.
`AccountKeyring::Alice.public().to_ss58check()`), which can be later
used in the any of built-in [_runtime-genesis-config_
variant](https://github.com/paritytech/polkadot-sdk/blob/21d36b7b4229c4d5225944f197918cde23fda4ea/polkadot/node/service/src/chain_spec.rs#L1066-L1073).


The proposal is as follows:
- expose [`core::Pair`
trait](https://github.com/paritytech/polkadot-sdk/blob/d6f15306282e3de848a09c9aa9cba6f95a7811f0/substrate/primitives/core/src/crypto.rs#L832)
in `no-std`,
- `full_crypto` feature enables `sign` method,
- `std` feature enables `generate_with_phrase` and `generate` methods
(randomness is required),
- All other functionality, currently gated by `full_crypto` will be
available unconditionally (`no-std`):
-- `from_string`
-- `from_string_with_seed`
-- `from seed`
-- `from_seed_slice`
-- `from_phrase`
-- `derive`
-- `verify`

---

Depends on https://github.com/rust-bitcoin/rust-bip39/pull/57

---------

Co-authored-by: command-bot <>
Co-authored-by: Davide Galassi <davxy@datawok.net>

substrate/primitives/core/Cargo.toml

@@ -27,10 +27,11 @@ hash-db = { version = "0.16.0", default-features = false }
 hash256-std-hasher = { version = "0.15.2", default-features = false }
 bs58 = { version = "0.5.0", default-features = false, optional = true }
 rand = { version = "0.8.5", features = ["small_rng"], optional = true }
-substrate-bip39 = { path = "../../utils/substrate-bip39", optional = true }
-bip39 = { version = "2.0.0", default-features = false }
+substrate-bip39 = { path = "../../utils/substrate-bip39", default-features = false }
+# personal fork here as workaround for: https://github.com/rust-bitcoin/rust-bip39/pull/64
+bip39 = { package = "parity-bip39", version = "2.0.1", default-features = false, features = ["alloc"] }
 zeroize = { version = "1.4.3", default-features = false }
-secrecy = { version = "0.8.0", default-features = false }
+secrecy = { version = "0.8.0", default-features = false, features = ["alloc"] }
 parking_lot = { version = "0.12.1", optional = true }
 ss58-registry = { version = "1.34.0", default-features = false }
 sp-std = { path = "../std", default-features = false }
@@ -46,13 +47,13 @@ paste = "1.0.7"
 itertools = { version = "0.10.3", optional = true }
 
 # full crypto
-array-bytes = { version = "6.1", optional = true }
-ed25519-zebra = { version = "3.1.0", default-features = false, optional = true }
+array-bytes = { version = "6.1" }
+ed25519-zebra = { version = "3.1.0", default-features = false }
 blake2 = { version = "0.10.4", default-features = false, optional = true }
-libsecp256k1 = { version = "0.7", default-features = false, features = ["static-context"], optional = true }
+libsecp256k1 = { version = "0.7", default-features = false, features = ["static-context"] }
 schnorrkel = { version = "0.11.4", features = ["preaudit_deprecated"], default-features = false }
 merlin = { version = "3.0", default-features = false }
-sp-crypto-hashing = { path = "../crypto/hashing", default-features = false, optional = true }
+sp-crypto-hashing = { path = "../crypto/hashing", default-features = false }
 sp-runtime-interface = { path = "../runtime-interface", default-features = false }
 # k256 crate, better portability, intended to be used in substrate-runtimes (no-std)
 k256 = { version = "0.13.3", features = ["alloc", "ecdsa"], default-features = false }
@@ -81,7 +82,6 @@ bench = false
 default = ["std"]
 
 std = [
-	"array-bytes",
 	"bandersnatch_vrfs?/std",
 	"bip39/rand",
 	"bip39/std",
@@ -112,7 +112,6 @@ std = [
 	"schnorrkel/std",
 	"secp256k1/global-context",
 	"secp256k1/std",
-	"secrecy/alloc",
 	"serde/std",
 	"sp-crypto-hashing/std",
 	"sp-debug-derive/std",
@@ -131,7 +130,6 @@ std = [
 
 # Serde support without relying on std features.
 serde = [
-	"array-bytes",
 	"blake2",
 	"bounded-collections/serde",
 	"bs58/alloc",
@@ -140,8 +138,6 @@ serde = [
 	"k256/serde",
 	"primitive-types/serde_no_std",
 	"scale-info/serde",
-	"secrecy/alloc",
-	"sp-crypto-hashing",
 	"sp-storage/serde",
 ]
 
@@ -149,11 +145,7 @@ serde = [
 # or Intel SGX.
 # For the regular wasm runtime builds this should not be used.
 full_crypto = [
-	"array-bytes",
 	"blake2",
-	"ed25519-zebra",
-	"libsecp256k1",
-	"sp-crypto-hashing",
 	"sp-runtime-interface/disable_target_static_assertions",
 ]