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/state-machine/Cargo.toml

@@ -28,7 +28,6 @@ tracing = { version = "0.1.29", optional = true }
 sp-core = { path = "../core", default-features = false }
 sp-externalities = { path = "../externalities", default-features = false }
 sp-panic-handler = { path = "../panic-handler", optional = true }
-sp-std = { path = "../std", default-features = false }
 sp-trie = { path = "../trie", default-features = false }
 trie-db = { version = "0.28.0", default-features = false }
 
@@ -51,7 +50,6 @@ std = [
 	"sp-externalities/std",
 	"sp-panic-handler",
 	"sp-runtime/std",
-	"sp-std/std",
 	"sp-trie/std",
 	"thiserror",
 	"tracing",