Use parcel for main and esm builds

[D4nte]

Resolves #579

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
build/esm/index.js	1.57 MB (+0.03% 🔺)	32.3 s (+0.03% 🔺)	1.7 s (+18.59% 🔺)	34 s

[D4nte]

Published to @waku/staging.
Looks good in React app.

However, with NodeJS, getting:

import {discovery} from "@waku/staging";
        ^^^^^^^^^
SyntaxError: Named export 'discovery' not found. The requested module '@waku/staging' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from '@waku/staging';
const {discovery} = pkg;

Ideally I'd like to enable user to use the import { foo } from "js-waku" syntax.

No luck so far in finding how to make parcel bundle it as it was done with tsc.

@prichodko, is that something you are familiar with?

[D4nte]

To be tried again once #803 is merged