Snowbridge: Support bridging native ETH (#6855)
Changes: 1. Use the 0x0000000000000000000000000000000000000000 token address as Native ETH. 2. Convert it to/from `{ parents: 2, interior: X1(GlobalConsensus(Ethereum{chain_id: 1})) }` when encountered. Onchain changes: This will require a governance request to register native ETH (with the above location) in the foreign assets pallet and make it sufficient. Related solidity changes: https://github.com/Snowfork/snowbridge/pull/1354 TODO: - [x] Emulated Tests --------- Co-authored-by: Vincent Geddes <[email protected]> Co-authored-by: Bastian Köcher <[email protected]> Co-authored-by: Bastian Köcher <[email protected]> (cherry picked from commit 4059282f)