Add guide-specific info

[apinnick]

Add the following info to each guide:

• Persona
• Goal

Benefits:

• Help contributors understand target audience and purpose of each guide
• Identify situations where a new guide might be required

Resources:

• Foreman docs call (Nov. 13, 2025)

Next steps:

• POC PR . Approved by reviewers.
• Approved by stakeholders
• Updated contributor guidelines

[apinnick]

In the PR, I added the information as a block comment in the 'master.adoc' file.

There were other possibilities that I considered:

• README.md: Very visible when files are viewed in a browser, not so visible in most authoring tools.
• docinfo.xml: Would be the most logical place, since the abstract and other metadata live there. However, it is a small file and easy to overlook.

[aneta-petrova]

In #4495 (comment), @apinnick asked whether we should add a few lines to the contribution guidelines about the guide metadata. IMO, that's not necessary: Including this sort of information in all master.adoc files should be sufficient.

[maximiliankolb]

I am open to all three places: master.adoc (my favorite), a README.md in guides/doc-*/, or in the XML files.