[Docs] Diagram representation of the chembl_webresource_client

[ivanmilevtues]

This PR adds an architectural diagram of the chembl_webresource_client codebase to help new contributors quickly understand its structure.

You can see how the change renders here: https://github.com/CodeBoarding/GeneratedOnBoardings/blob/main/chembl_webresource_client/on_boarding.md

I would love to hear what do you think of auto generate diagram first documentation. This way it can always be up-to-date, (generated with Static Analysis and LLMs) if you like what you see I'd be more than happy to also make a PR with our free to use github action :)

Since Discussions aren’t enabled, I’m sharing this via PR.

Disclamer: We're doing this as part of an early-stage startup, exploring what’s most helpful for OSS maintainers.

[ivanmilevtues]

Hey, a quick update on our side, this week we released our diagram generaiton engine as an open-source project! If you are interested to see more on how the generation works you can do so at https://github.com/CodeBoarding/CodeBoarding