Exploration: How to visualize what is where?

When I started reading the MVG I had a bit of a hard time figuring out what is where, and what each file is meant to be used for.

I have some ideas but I don't fully know where I am going with this so rather than sending a PR for it right away, I am exploring the options here.

### Idea 1: Formatting the two main folders in the README slightly differently

The [README](https://github.com/github/MVG/blame/main/README.md#L7) could make it more obvious that the main structure are these two folders.

It could look similar to this:

> There are two folders:
> * **org-docs**: Provides top-level organizational governance and polices for a technical steering committee (TSC).
> * **project-docs**: Provides a template for individual project governance, subject to the polices and oversight of the larger organization.

### Idea 2: Tree structure

Listing the main files in the README would allow to explain where to start, and what the purpose of each file is.

For example:

```
org-docs/
├── ANTITRUST.md - ...
├── CHARTER.md <= Start here
├── CODE-OF-CONDUCT.md - Code of Conduct based on the Contributor Covenant.
├── STEERING-COMMITTEE.md - Lists the voting members of the Steering Committee
└── TRADEMARKS.md - ...

project-docs/
├── CONTRIBUTING.md - ...
├── GOVERNANCE.md <= Start here
├── LICENSE.md - ...
└── MAINTAINERS.md - Lists the Maintainers of the Project
```

Alternatively one could add a new README.md file to each of the folders.
Those would serve as index pages, explaining what each file is meant to be used for.

So much for now. Looking forward to hear your thoughts on this.

Start with README.md and compare the org-docs and project-docs trees listed in the issue. Review the discussion around the proposed navigation approaches; done would be a decided README or per-folder index structure that explains each listed file and where to start.

索引モデルが issue の本文から書いたものです。