[policy, no patch] Define content of Status page

Problem/Motivation

#3614730: CKEditor version should be shown in the Status report suggests adding the CKEditor version to the Status report page. Since I questioned if that should be done I went looking for some documentation on what should be on the page and didn't find any.

I also brought this up with committers. xjm recalled that in previous discussions about the page that items on the page should be actionable. longwave suggested a UX review because of useless unstructured information. We didn't go into details about what is 'useless'.

Steps to reproduce

Proposed resolution

Publish guidelines in the Core Change policies to clarify

1. the audience for the status report page
2. what type of information should be on the page
3. what type of information should not be on the page

Remaining tasks

Create guidelines for the content, not design, of the page and define the intended audience.

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet