RFP (Request for Proposals) : Support send runtime calls using wallets like metamask

[hackfisher]

This can be easily constructed by the runtime calls component and dispatch js SDK

[hackfisher]

There is existing solution(thanks to @hujw77 ) using remix with the following contract's support:

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

contract Dispatch {
    fallback (bytes calldata _input) external payable returns (bytes memory _output)   {} 
}

[
	{
		"stateMutability": "payable",
		"type": "fallback"
	}
]

Compile this contract using remix first, then connect to you account using Inject Provider, copy dispatch precompile address and the encoded runtime call data from polkadot js:

Refer following interfaces:

https://docs.darwinia.network/builtin-precompiles-38faea0d12a648e9a061cf013e1cfdd6

[wuminzhe]

https://jsfiddle.net/wuminzhe/5qx0pcej/1/

In vscode, there will be auto-completions.

[hackfisher]

This is for developer, not for app user, as we already have a solidity solution for it, let's move it to documentation.