initial upload

[vincerubinetti]

• replaces hcluster.js by @cmpolis
• in general, faster and more efficient than hcluster.js, with equivalent functionality
• more modern javascript syntax to be cleaner and more readable

[dongbohu]

Left a few comments.

[vincerubinetti]

Added a github actions workflow to publish package to npm. Don't merge until these two questions are answered:
mikeal/merge-release#13 (comment)
mikeal/merge-release#9 (comment)

[vincerubinetti]

@dongbohu @dhimmel Could you take a quick look at this commit regarding github actions, and this specific action.

I created a greenelab org on npm and created an auth token, and added it as a secret to this repo under NPM_AUTH_TOKEN. But I don't have to specify the org in the gh-actions workflow? I guess the auth token is enough to identify which org to publish the package to.

[cgreene]

This looks really nice! I had just a few minor comments.

[dhimmel]

the action part looks good to me!

[dongbohu]

The git action part looks good to me too.