[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/integration-tests/emulated/assets/asset-hub-rococo/src/tests/reserve_transfer.rs

@@ -249,15 +249,15 @@ fn reserve_transfer_native_asset_from_relay_to_system_para_fails() {
 	test.set_dispatchable::<Rococo>(relay_reserve_transfer_assets);
 	test.assert();
 
-	let sender_balance_after = test.sender.balance;
-	let receiver_balance_after = test.receiver.balance;
-
 	let delivery_fees = Rococo::execute_with(|| {
 		xcm_helpers::transfer_assets_delivery_fees::<
 			<RococoXcmConfig as xcm_executor::Config>::XcmSender,
 		>(test.args.assets.clone(), 0, test.args.weight_limit, test.args.beneficiary, test.args.dest)
 	});
 
+	let sender_balance_after = test.sender.balance;
+	let receiver_balance_after = test.receiver.balance;
+
 	assert_eq!(sender_balance_before - amount_to_send - delivery_fees, sender_balance_after);
 	assert_eq!(receiver_balance_before, receiver_balance_after);
 }