Generate input/output interface for circom.

[vuvoth]

Motivation

We are using snarkjs as backend for circom.

     const { proof, publicSignals } = await snarkjs.groth16.fullProve(
            inputs,
            circuitWasmPath,
            zkeyPath
     )

Variable inputs have type any. Every time we changed circom file we need to update inputs structs. However any make us hard to remember and easy to create error/bugs.
I think we should create function for auto gen inputs/outputs interface of circom. It's help developer easy to test and use circom.

Proposal

Create new interface command line to generate inputs/outputs interface.

Example

circom merkle_tree.circom --types types.ts

Circom file

include "../../../node_modules/circomlib/circuits/comparators.circom";

template Example() {
    signal input first_input;
    signal input second_input[100];
    signal output first_output;
}

We will generate inputs interface like bellow:

interface ExampleInput {
    first_input: bigint;
    second_input: bigint[];
}

Samething for outputs interface.

Thank Iden3 for awesome work!