refactor: Transaction-Payment module (#3816)

* Initial draft that compiles

* Extract payment stuff from balances

* Extract multiplier update stuff from system

* Some fixes.

* Update len-fee as well

* some review comments.

* Remove todo

* bump

substrate/subkey/Cargo.toml

@@ -19,6 +19,7 @@ hex-literal = "0.2.1"
 codec = { package = "parity-scale-codec", version = "1.0.0" }
 system = { package = "srml-system", path = "../srml/system" }
 balances = { package = "srml-balances", path = "../srml/balances" }
+transaction-payment = { package = "srml-transaction-payment", path = "../srml/transaction-payment" }
 
 [features]
 bench = []

substrate/subkey/src/main.rs

@@ -363,7 +363,7 @@ fn create_extrinsic(
 			system::CheckEra::<Runtime>::from(Era::Immortal),
 			system::CheckNonce::<Runtime>::from(i),
 			system::CheckWeight::<Runtime>::new(),
-			balances::TakeFees::<Runtime>::from(f),
+			transaction_payment::ChargeTransactionPayment::<Runtime>::from(f),
 			Default::default(),
 		)
 	};