frame: support for serde added (#14261)

* frame: support for serde added

- enabled `serde` features in dependent crates, no gate feature introduced, linker should do the job and strip unused code.

- frame::staking: added impl of `serde::Serialize, serde::Deserialize` for `enum Forcing`

- primitives::runtime: impl_opaque_keys macro provides `Serialize/Deserialize` impl if `serde` is enabled

- primitives::staking: added impl of `serde::Serialize`, `serde::Deserialize` for `enum StakerStatus`

* frame::support: serde for pallets' GenesisConfig enabled in no-std

* Cargo.lock updated

* Update primitives/staking/Cargo.toml

Co-authored-by: Bastian Köcher <git@kchr.de>

* fix

* Cargo.lock update + missed serde/std in beefy

---------

Co-authored-by: Bastian Köcher <git@kchr.de>

substrate/frame/staking/src/lib.rs

@@ -849,8 +849,19 @@ impl<Balance: AtLeast32BitUnsigned + Clone, T: Get<&'static PiecewiseLinear<'sta
 }
 
 /// Mode of era-forcing.
-#[derive(Copy, Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug, TypeInfo, MaxEncodedLen)]
-#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[derive(
+	Copy,
+	Clone,
+	PartialEq,
+	Eq,
+	Encode,
+	Decode,
+	RuntimeDebug,
+	TypeInfo,
+	MaxEncodedLen,
+	serde::Serialize,
+	serde::Deserialize,
+)]
 pub enum Forcing {
 	/// Not forcing anything - just let whatever happen.
 	NotForcing,