Docs: improve onboarding and readability of docs

Hello,
I am new to octokit and this pull request plugin, but nonetheless I wish to contribute my piece for it, since I do see the value and it worked awesome when i got it setup.
When I started using it it was slightly difficult to start using, at least using a minimal version for it, for my needs at the time. It was more heavily focused on giving all info available, than some quick setup or start guide, which I obviously think is good, but slightly hard for beginners.

Would the maintainers be open to a PR that reorganizes the documentation? I would take a pass at splitting the README into clearer sections, adding (something similar to):

- A bare-minimum, copy-pasteable "Quick Start" example.

- A sequential workflow/tutorial approach to the more complex, multi-file features.

- A clear separation between the quick-start guides and the deep-dive API reference.

For me, this is a great opportunity to get to know the codebase inside and out. Once I have a solid draft ready, I’d love to get your feedback and iterate on it until we have something awesome.

Any thoughts or preferences on this before I dive in?

Thanks!

Start by reading the existing README and identify how its current setup and API information are organized. Draft a clearer structure with a bare-minimum Quick Start, a sequential tutorial for multi-file features, and a separate deep-dive reference. Done means the README is easier for beginners to follow while preserving the detailed information.

Written by the indexing model from the issue text.