Docs: How Renovate Works overview

[rarkins]

Describe the proposed change(s).

Add a "How Renovate Works" high level overview for people who wish to understand the internals a little better. e.g. global config load, platforms, modules, datasources, and the overview "flow" (including cleaning up stale branches).

Discussed in #11237 (comment) and onwards

[azro352]

I'd like to propose myself to try that , after using several features I was disappointed that the doc doesn't explai much the flow and the parts of it. So i've already started to navigate through the code

I've started to write that down as a mermaid graph, but I'm unsure if it will be easy to render that in the github pages (need to create hml and load mermaid.js)

May I open a PR and link to this ?

[HonkingGoose]

Our docs generating framework can show Mermaid diagrams. We only need to change the docs configuration.

I suspect that the Mermaid diagrams are useless if you can't see well. So we also need to have the explanation in plain text.

Material for MkDocs, diagram support

[renovate-release]

🎉 This issue has been resolved in version 37.105.1 🎉

The release is available on:

• GitHub release
• 37.105.1

Your semantic-release bot 📦🚀