feat: updated, refactored and cleaned up

[ovflowd]

This PR removes the usage of very old dependencies for the ones maintained officially by Google with updated APIs.

This PR refactors and modularizes the source code and ensures it is functional via environmnent-based configuration, instead of fie-system ones.

It also amplifies the code, documentation and ensures it is easy to contribute towards.

[mhdawson]

I think it would be good to get the updated version working/tested in real life before landing changes to the repo. I won't have time to debug if changes break the live tooling which regularly updates from this repo to pull in changes.

[ovflowd]

I think it would be good to get the updated version working/tested in real life before landing changes to the repo. I won't have time to debug if changes break the live tooling which regularly updates from this repo to pull in changes.

+1. I haven't tested this for real yet, so we shouldn't land before I'm able to confirm it works fine. Would unit testing also make sense here?

[ovflowd]

• https://hackmd.io/@hackmd-api/developer-portal/https%3A%2F%2Fapi.hackmd.io%2Fv1%2Fdocs
• https://api.hackmd.io/v1/docs
• https://github.com/hackmdio/api-client/tree/develop/nodejs

Adding HackMD docs as we're closing a partnership with'em.

[ovflowd]

cc @avivkeller ☝️

[ovflowd]

FYI this PR staled a bit as I'm going to work next weekend on (Aiming the Sunday or Saturday) (16th/17th of August)

[ovflowd]

cc @mhdawson this PR is ready to be reviewed and merged once we set the tokens 🙇

[ovflowd]

@bensternthal / @ryanaslett I'm ready to set the tokens once openjs-foundation/infrastructure#78 gets done.

[avivkeller]

The remaining comments of mine are nitpicks.

LGTM, thank you, Claudio!