Move LockableCurrency trait to fungibles::Lockable and deprecate LockableCurrency (#12798)

* WIP move LockableCurrency to fungibles

* rename Lockable and LockIdentifier to funginbles::*

* fix imports further

* change Lockable from fungible to fungibles

* reintroduce LockableCurrency but marked as deprecated

* fix imports

* fix imports

* cargo fmt

* add allow deprecated warnings

* remove unused benchmark import

* fix some of the docs

* fix failing doctest check

* reexport LockIdentifier and LockableCurrency from support/traits

* reexport LockIdentifier and LockableCurrency from support/traits

* allow using deprecated re-export

* replace LockableCurrency and LockIdentifier with a module alias

* Update frame/support/src/traits/tokens/fungibles/lockable.rs

* Update frame/staking/src/pallet/mod.rs

Co-authored-by: Squirrel <gilescope@gmail.com>

* Update frame/support/src/traits.rs

Co-authored-by: Squirrel <gilescope@gmail.com>

* REVERT removing fungibles::Lockable import

Co-authored-by: parity-processbot <>
Co-authored-by: Squirrel <gilescope@gmail.com>

substrate/frame/democracy/src/lib.rs

@@ -157,9 +157,11 @@ use frame_support::{
 	ensure,
 	traits::{
 		defensive_prelude::*,
+		fungibles,
+		fungibles::Lockable,
 		schedule::{v3::Named as ScheduleNamed, DispatchTime},
-		Bounded, Currency, Get, LockIdentifier, LockableCurrency, OnUnbalanced, QueryPreimage,
-		ReservableCurrency, StorePreimage, WithdrawReasons,
+		Bounded, Currency, Get, OnUnbalanced, QueryPreimage, ReservableCurrency, StorePreimage,
+		WithdrawReasons,
 	},
 	weights::Weight,
 };
@@ -189,7 +191,7 @@ pub mod benchmarking;
 
 pub mod migrations;
 
-const DEMOCRACY_ID: LockIdentifier = *b"democrac";
+const DEMOCRACY_ID: fungibles::LockIdentifier = *b"democrac";
 
 /// A proposal index.
 pub type PropIndex = u32;
@@ -234,7 +236,7 @@ pub mod pallet {
 
 		/// Currency type for this pallet.
 		type Currency: ReservableCurrency<Self::AccountId>
-			+ LockableCurrency<Self::AccountId, Moment = Self::BlockNumber>;
+			+ fungibles::Lockable<Self::AccountId, Moment = Self::BlockNumber>;
 
 		/// The period between a proposal being approved and enacted.
 		///