Chore: Edit down `README.md` and update to latest Tech Stack

[nelsonic]

At present the initial README.md of this repo is a bit "ramble-y" ... 🙃
I think we could/should either trim it down by at least half ✂️
or even re-write it completely to joint point people to the book: https://dwyl.github.io/book 💭

Todo

• Decide if there is anything in the current README.md that is worth keeping.
• Re-work the README.md so that it gives just enough info about what we're doing.
• Then link to the book.
• Question: should we host the book on a subdomain e.g: book.dwyl.com for SEO? 💭