contracts: Expose rent parameter to contracts (#8231)

* contracts: Expose rent parameter to contracts

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_contracts --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/contracts/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* Fix typos

* Improve comments

* Add rent parameter weights

* Allow deploying a new schedule with the same version

* Add storage migration for new schedule

* Only decode the schedule version in storage migration

* Remove confusing docs

* Replace original_code_len() by aggregate_code_len()

Co-authored-by: Parity Benchmarking Bot <admin@parity.io>

substrate/frame/contracts/src/migration.rs

@@ -0,0 +1,45 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2018-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::{Config, Weight, CurrentSchedule, Pallet, Schedule};
+use frame_support::traits::{GetPalletVersion, PalletVersion, Get};
+
+pub fn migrate<T: Config>() -> Weight {
+	let mut weight: Weight = 0;
+
+	match <Pallet<T>>::storage_version() {
+		// Replace the schedule with the new default and increment its version.
+		Some(version) if version == PalletVersion::new(3, 0, 0) => {
+			weight = weight.saturating_add(T::DbWeight::get().reads_writes(1, 1));
+			let _ = <CurrentSchedule<T>>::translate::<u32, _>(|version| {
+				if let Some(version) = version {
+					Some(Schedule {
+						version: version.saturating_add(1),
+						// Default limits were not decreased. Therefore it is OK to overwrite
+						// the schedule with the new defaults.
+						.. Default::default()
+					})
+				} else {
+					None
+				}
+			});
+		}
+		_ => (),
+	}
+
+	weight
+}