Make resources standalone files

[mhchia]

What’s wrong?

Default resources (.zkey and .wasm) generated by snarkjs are encoded in base64 and put inside typescript files. It's a workaround. They should be individual files originally since it's easier to maintain and it allows developers to decide whether or not to load a file. base64 approach has been used because I find it harder to make RLNjs work with standalone files while supporting both browser and nodejs.

How to fix it?

At the moment I can only think of using environment variables to determine whether it's in the browser or nodejs, and access resources in different ways. Maybe there is a better approach though.

[mhchia]

I didn't label it "good first issue" since it might be troublesome. But feel free to fix it if you have any ideas.

[mhchia]

Thanks to the suggestion from @0xtsukino , if we have a static server hosting resources, it will be a lot easier to support the browser by fetching the resource by URL.

Below is referenced from zkitter-js

  const wasmResp = await fetch(`https://api.zkitter.com/circuits/rln/wasm`);
  const wasmbuf = Buffer.from(await wasmResp.arrayBuffer());
  const zkeyResp = await fetch(`https://api.zkitter.com/circuits/rln/zkey`);
  const zkeybuf = Buffer.from(await zkeyResp.arrayBuffer());