Set up the `TakeFirstAssetTrader` trader for Westend and Rococo Asset
Hubs to cover XCM fees with sufficient assets.
This PR reintroduces previously
[removed](https://github.com/paritytech/polkadot-sdk/pull/1845) trader
setups, as it was decided to keep both traders, `TakeFirstAssetTrader`
and `SwapFirstAssetTrader`, during the transition period.
---------
Co-authored-by: Svyatoslav Nikolsky <svyatonik@gmail.com>