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/crypto/ec-utils/src/utils.rs

@@ -21,6 +21,7 @@
 // curve may be excluded by the build we resort to `#[allow(unused)]` to
 // suppress the expected warning.
 
+use alloc::vec::Vec;
 use ark_ec::{
 	pairing::{MillerLoopOutput, Pairing},
 	short_weierstrass::{Affine as SWAffine, Projective as SWProjective, SWCurveConfig},
@@ -31,7 +32,6 @@ use ark_scale::{
 	ark_serialize::{CanonicalDeserialize, CanonicalSerialize, Compress, Validate},
 	scale::{Decode, Encode},
 };
-use sp_std::vec::Vec;
 
 // SCALE encoding parameters shared by all the enabled modules
 const SCALE_USAGE: u8 = ark_scale::make_usage(Compress::No, Validate::No);