[testnet] Add AssetHubRococo <-> AssetHubWestend asset bridging support (#1967)

## Summary

Asset bridging support for AssetHub**Rococo** <-> AssetHub**Wococo** was
added [here](https://github.com/paritytech/polkadot-sdk/pull/1215), so
now we aim to bridge AssetHub**Rococo** and AssetHub**Westend**. (And
perhaps retire AssetHubWococo and the Wococo chains).

## Solution

**bridge-hub-westend-runtime**
- added new runtime as a copy of `bridge-hub-rococo-runtime`
- added support for bridging to `BridgeHubRococo`
- added tests and benchmarks

**bridge-hub-rococo-runtime**
- added support for bridging to `BridgeHubWestend`
- added tests and benchmarks
- internal refactoring by splitting bridge configuration per network,
e.g., `bridge_to_whatevernetwork_config.rs`.

**asset-hub-rococo-runtime**
- added support for asset bridging to `AssetHubWestend` (allows to
receive only WNDs)
- added new xcm router for `Westend`
- added tests and benchmarks

**asset-hub-westend-runtime**
- added support for asset bridging to `AssetHubRococo` (allows to
receive only ROCs)
- added new xcm router for `Rococo`
- added tests and benchmarks

## Deployment

All changes will be deployed as a part of
https://github.com/paritytech/polkadot-sdk/issues/1988.

## TODO

- [x] benchmarks for all pallet instances
- [x] integration tests
- [x] local run scripts


Relates to:
https://github.com/paritytech/parity-bridges-common/issues/2602
Relates to: https://github.com/paritytech/polkadot-sdk/issues/1988

---------

Co-authored-by: command-bot <>
Co-authored-by: Adrian Catangiu <adrian@parity.io>
Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/bridge_common_config.rs

@@ -0,0 +1,50 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Cumulus is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Cumulus is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Bridge definitions that can be used by multiple BridgeHub flavors.
+//! All configurations here should be dedicated to a single chain; in other words, we don't need two
+//! chains for a single pallet configuration.
+//!
+//! For example, the messaging pallet needs to know the sending and receiving chains, but the
+//! GRANDPA tracking pallet only needs to be aware of one chain.
+
+use super::{weights, AccountId, Balance, Balances, BlockNumber, Runtime, RuntimeEvent};
+use frame_support::parameter_types;
+
+parameter_types! {
+	pub storage RequiredStakeForStakeAndSlash: Balance = 1_000_000;
+	pub const RelayerStakeLease: u32 = 8;
+	pub const RelayerStakeReserveId: [u8; 8] = *b"brdgrlrs";
+
+	pub storage DeliveryRewardInBalance: u64 = 1_000_000;
+}
+
+/// Allows collect and claim rewards for relayers
+impl pallet_bridge_relayers::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type Reward = Balance;
+	type PaymentProcedure =
+		bp_relayers::PayRewardFromAccount<pallet_balances::Pallet<Runtime>, AccountId>;
+	type StakeAndSlash = pallet_bridge_relayers::StakeAndSlashNamed<
+		AccountId,
+		BlockNumber,
+		Balances,
+		RelayerStakeReserveId,
+		RequiredStakeForStakeAndSlash,
+		RelayerStakeLease,
+	>;
+	type WeightInfo = weights::pallet_bridge_relayers::WeightInfo<Runtime>;
+}