sp-std removal from substrate/primitives (#3274)

This PR removes sp-std crate from substrate/primitives sub-directories.

For now crates that have `pub use` of sp-std or export macros that would
necessitate users of the macros to `extern crate alloc` have been
excluded from this PR.

There should be no breaking changes in this PR.

---------

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

substrate/primitives/consensus/beefy/src/lib.rs

@@ -31,6 +31,8 @@
 //! it will use a different set of keys. For Polkadot use case we plan to use `secp256k1` for BEEFY,
 //! while GRANDPA uses `ed25519`.
 
+extern crate alloc;
+
 mod commitment;
 mod payload;
 
@@ -44,13 +46,13 @@ pub mod test_utils;
 pub use commitment::{Commitment, SignedCommitment, VersionedFinalityProof};
 pub use payload::{known_payloads, BeefyPayloadId, Payload, PayloadProvider};
 
+use alloc::vec::Vec;
 use codec::{Codec, Decode, Encode};
 use core::fmt::{Debug, Display};
 use scale_info::TypeInfo;
 use sp_application_crypto::{AppCrypto, AppPublic, ByteArray, RuntimeAppPublic};
 use sp_core::H256;
 use sp_runtime::traits::{Hash, Keccak256, NumberFor};
-use sp_std::prelude::*;
 
 /// Key type for BEEFY module.
 pub const KEY_TYPE: sp_core::crypto::KeyTypeId = sp_application_crypto::key_types::BEEFY;