feat: ParaToEthereum

[marshacb]

Description

This PR adds support for constructing txs sending Snowbridge ERC20 tokens from a parachain origin back to Ethereum via Snowbridge.

Example usage:

const xcmVersion = 4;
const { api, specName } = await constructApiPromise('wss://hydradx-rpc.dwellir.com');
const assetApi = new AssetTransferApi(api, specName, xcmVersion, {
  injectedRegistry: {
	  polkadot: {
		  2034: {
			  xcAssetsData: [
				  {
					  symbol: 'WETH.snow',
					  xcmV1MultiLocation:
						  '{"v1":{"parents":2,"interior":{"x2":[{"globalConsensus":{"ethereum":{"chainId":1}}},{"accountKey20":{"network":null,"key":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"}}]}}}',
				  },
			  ],
		  },
	  },
  },
});

let callInfo: TxResult<'call'>;
try {
callInfo = await assetApi.createTransferTransaction(
	`{"parents":"2","interior":{"X1":{"GlobalConsensus":{"Ethereum":{"chainId":"1"}}}}}`,
	'0x6E733286C3Dc52C67b8DAdFDd634eD9c3Fb05B5B',
	['DOT', 'WETH.snow'],
	['70000000000', '75000000000000'],
	{
		sendersAddr: '7KqMfyEXGMAgkNGxiTf3PNgKqSH1WNghbAGLKezYyLLW4Zp1',
		format: 'call',
		xcmVersion,
		paysWithFeeDest: 'DOT', // Asset to be used to pay for fees on destination chain
	},
);

console.log(callInfo);

Expected output:

{
  origin: 'hydradx',
  dest: 'ethereum',
  direction: 'ParaToEthereum',
  xcmVersion: 4,
  method: 'transferAssetsUsingTypeAndThen',
  format: 'call',
  tx: '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'
}

The following decoded tx:
 {
    "args": {
        "dest": {
            "V4": {
                "parents": "1",
                "interior": {
                    "X1": [
                        {
                            "Parachain": "1,000"
                        }
                    ]
                }
            }
        },
        "assets": {
            "V4": [
                {
                    "id": {
                        "parents": "1",
                        "interior": "Here"
                    },
                    "fun": {
                        "Fungible": "70,000,000,000"
                    }
                },
                {
                    "id": {
                        "parents": "2",
                        "interior": {
                            "X2": [
                                {
                                    "GlobalConsensus": {
                                        "Ethereum": {
                                            "chainId": "1"
                                        }
                                    }
                                },
                                {
                                    "AccountKey20": {
                                        "network": null,
                                        "key": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
                                    }
                                }
                            ]
                        }
                    },
                    "fun": {
                        "Fungible": "75,000,000,000,000"
                    }
                }
            ]
        },
        "assets_transfer_type": "DestinationReserve",
        "remote_fees_id": {
            "V4": {
                "parents": "1",
                "interior": "Here"
            }
        },
        "fees_transfer_type": "DestinationReserve",
        "custom_xcm_on_dest": {
            "V4": [
                {
                    "SetAppendix": [
                        {
                            "DepositAsset": {
                                "assets": {
                                    "Wild": "All"
                                },
                                "beneficiary": {
                                    "parents": "0",
                                    "interior": {
                                        "X1": [
                                            {
                                                "AccountId32": {
                                                    "network": null,
                                                    "id": "0x62fecf9c60d8d49d400bd86804558401ec7151fecd440041ca6bf5fd57825177"
                                                }
                                            }
                                        ]
                                    }
                                }
                            }
                        }
                    ]
                },
                {
                    "InitiateReserveWithdraw": {
                        "assets": {
                            "Wild": {
                                "AllOf": {
                                    "id": {
                                        "parents": "2",
                                        "interior": {
                                            "X2": [
                                                {
                                                    "GlobalConsensus": {
                                                        "Ethereum": {
                                                            "chainId": "1"
                                                        }
                                                    }
                                                },
                                                {
                                                    "AccountKey20": {
                                                        "network": null,
                                                        "key": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
                                                    }
                                                }
                                            ]
                                        }
                                    },
                                    "fun": "Fungible"
                                }
                            }
                        },
                        "reserve": {
                            "parents": "2",
                            "interior": {
                                "X1": [
                                    {
                                        "GlobalConsensus": {
                                            "Ethereum": {
                                                "chainId": "1"
                                            }
                                        }
                                    }
                                ]
                            }
                        },
                        "xcm": [
                            {
                                "BuyExecution": {
                                    "fees": {
                                        "id": {
                                            "parents": "0",
                                            "interior": {
                                                "X1": [
                                                    {
                                                        "AccountKey20": {
                                                            "network": null,
                                                            "key": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
                                                        }
                                                    }
                                                ]
                                            }
                                        },
                                        "fun": {
                                            "Fungible": "1"
                                        }
                                    },
                                    "weightLimit": "Unlimited"
                                }
                            },
                            {
                                "DepositAsset": {
                                    "assets": {
                                        "Wild": {
                                            "AllCounted": "1"
                                        }
                                    },
                                    "beneficiary": {
                                        "parents": "0",
                                        "interior": {
                                            "X1": [
                                                {
                                                    "AccountKey20": {
                                                        "network": null,
                                                        "key": "0x6e733286c3dc52c67b8dadfdd634ed9c3fb05b5b"
                                                    }
                                                }
                                            ]
                                        }
                                    }
                                }
                            },
                            {
                                "SetTopic": "0x0000000000000000000000000000000000000000000000000000000000000000"
                            }
                        ]
                    }
                },
                {
                    "SetTopic": "0x0000000000000000000000000000000000000000000000000000000000000000"
                }
            ]
        },
        "weight_limit": "Unlimited"
    },
    "method": "transferAssetsUsingTypeAndThen",
    "section": "polkadotXcm"
}

[bee344]

LGTM