Improve CJS and ESM module support

[d98762625]

Functional changes:

• Can now use chef with CJS and ES Modules
• use exports in package.json to explicitly define entrypoints for import and require routes
• can now use named imports with NodeJS v12+

load via require
Loading via require will take you to the esm wrapped module which exports the top-level ESModule as a CJS module. This provides full compatibility with ESM modules, but loading takes a performance hit, as shown in this PR

Performance profile

console.time('require');
require('cyberchef')
console.timeEnd('require');

// => require: 6313.314ms

load via import
Node.js as increasing support for ESM / CJS interoperability. We can use this with a couple of extra flags. A consumer will need to use --experimental-json-modules to load JSON files as modules, and --experimental-specifier-resolution to resolve non-explicit imports in our dependencies.

Performance profile

console.time('import');
import chef from "cyberchef";
console.timeEnd('import');

// => import: 0.110ms

Later Node.js versions
I've tested this with latest stable (14.3.0) - you don't need the --experimental-modules flag but you do need the other two when using import.