What data belongs in web-features

[atopal]

In the WebDX CG call on August 29, 2024 we discussed guidelines on how to associate data with web-features. The two options we have used in the past are:

1. Adding a field to web-features that links or associates the web-feature with data in some other place (eg caniuse)
2. Tagging data with a web-feature identifier (eg Web Platform Tests)

In the call the consensus was that by default we only maintain data in web-features that we require to determine the shape of a web feature. For all other kinds of data, we'll make case by case decisions where there is high utility for associating the data with web-features, but tagging is impossible or very impractical.

Opening it up for discussion here, before we add to the docs.