[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>

bridges/zombienet/helpers/best-finalized-header-at-bridged-chain.js

@@ -0,0 +1,25 @@
+async function run(nodeName, networkInfo, args) {
+    const {wsUri, userDefinedTypes} = networkInfo.nodesByName[nodeName];
+    const api = await zombie.connect(wsUri, userDefinedTypes);
+
+    // TODO: could be replaced with https://github.com/polkadot-js/api/issues/4930 (depends on metadata v15) later
+    const bridgedChainName = args[0];
+    const expectedBridgedChainHeaderNumber = Number(args[1]);
+    const runtimeApiMethod = bridgedChainName + "FinalityApi_best_finalized";
+
+    while (true) {
+        const encodedBestFinalizedHeaderId = await api.rpc.state.call(runtimeApiMethod, []);
+        const bestFinalizedHeaderId = api.createType("Option<BpRuntimeHeaderId>", encodedBestFinalizedHeaderId);
+        if (bestFinalizedHeaderId.isSome) {
+            const bestFinalizedHeaderNumber = Number(bestFinalizedHeaderId.unwrap().toHuman()[0]);
+            if (bestFinalizedHeaderNumber > expectedBridgedChainHeaderNumber) {
+                return bestFinalizedHeaderNumber;
+            }
+        }
+
+        // else sleep and retry
+        await new Promise((resolve) => setTimeout(resolve, 12000));
+    }
+}
+
+module.exports = { run }