ES Modules based ComponentLoader

[bergie]

Currently we have two ComponentLoader options:

• CommonJS based loader used normally for Node.js NoFlo programs
• "Hardcoded" component loader baked in with noflo-component-loader in Webpack builds

Nowadays browsers generally support Modules including dynamic imports. Node.js is also getting there. So, we should add a Module ComponentLoader option into NoFlo.

Using Modules would be especially interesting on browser, as it could allow loading components from various libraries as needed instead of having to have a "kitchen sink" build. A module loader should be possible to supply with a set of "fbp manifest" files telling where various components are available. It would then use dynamic loading to pull them in.

It would also open the door for making NoFlo available in tools like jsfiddle, as requested in #102 and #101

[bergie]

Once we have this in place, it might make sense to have a CI/CD process for NoFlo component libraries that would publish their component files and a fbp.json on GitHub Pages.