Support for `keyring` in runtimes (#2044)
This functionality is required for #1984. This PR enables [`sp-keyring`](https://github.com/paritytech/polkadot-sdk/blob/21d36b7b/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/21d36b7b/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/d6f15306 /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 <[email protected]>