Refactor: Rewrite Rings chains and assets

[arrudagates]

The current implementation of having chains and then chains with nested assets works fine, but it gets messy, a better implementation separating assets from chains would be preferable in the future, along with also accepting raw MultiLocation and MultiAsset in separate extrinsic functions.

The separation of chains and assets would also mean we can easily reanchor everything indiscriminately as we would consider everything to be in a sort of "absolute" state and regardless of origin/destination, we could just reanchor to turn the "absolute" state into a "relative" state.