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/arithmetic/Cargo.toml

@@ -26,7 +26,6 @@ num-traits = { version = "0.2.17", default-features = false }
 scale-info = { version = "2.10.0", default-features = false, features = ["derive"] }
 serde = { features = ["alloc", "derive"], optional = true, workspace = true }
 static_assertions = "1.1.0"
-sp-std = { path = "../std", default-features = false }
 
 [dev-dependencies]
 criterion = "0.4.0"
@@ -42,7 +41,6 @@ std = [
 	"scale-info/std",
 	"serde/std",
 	"sp-crypto-hashing/std",
-	"sp-std/std",
 ]
 # Serde support without relying on std features.
 serde = ["dep:serde", "scale-info/serde"]