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/client/cli/Cargo.toml

@@ -32,7 +32,8 @@ rpassword = "7.0.0"
 serde = { workspace = true, default-features = true }
 serde_json = { workspace = true, default-features = true }
 thiserror = { workspace = true }
-bip39 = "2.0.0"
+# personal fork here as workaround for: https://github.com/rust-bitcoin/rust-bip39/pull/64
+bip39 = { package = "parity-bip39", version = "2.0.1", features = ["rand"] }
 tokio = { version = "1.22.0", features = ["parking_lot", "rt-multi-thread", "signal"] }
 sc-client-api = { path = "../api" }
 sc-client-db = { path = "../db", default-features = false }