Support bridged token transfers from any chain

[IkerAlus]

At the moment the API does not allow the user to set a global consensus systems as destination of the transfers (in order to perform a transfer of assets to a different ecosystem via the Bridge Hub).

To support this feature, the input params of the API will need to be adapted to a string beyond just the paraID as it is currently. Potentially, the destination address format/typing may need to be expanded too.

In terms of directions, it may make sense to introduce two (or three) new directions:

• systemToBridge (should be covered by the new transferAssets call of pallet XCM.
• paraToBridge (currently not supported by paras runtime).
• RelayToBridge (to transfer the native DOT/KSM to a different eco).

Related issue: #371