[Request][Fleet] Adjust documentation to include info about bundled packages

[jen-huang]

Description

Related to effort in elastic/kibana#112095

We need docs for:

• Improving info about preconfiguration, make it a top-level docs section (if it isn't already)
• Add information about bundled packages within preconfiguration section
• Add to existing documentation on air-gapped environments about how bundled packages relate to that exprience

Collaboration

• The docs team will define with product team the structure and location, and the product team will provide the initial content

Contact Person: @kpollich

Suggested Target Release

8.2

Stakeholders

@joshdover

[joshdover]

I think we were going to cover this as part of elastic/ingest-docs#113, @kpollich was that your thinking too?

[kpollich]

@joshdover Generally, yes. @jen-huang mentioned documenting preconfiguration in detail with this issue though, which the other issue doesn't cover. We could probably combine these.

[joshdover]

Closing as a dupe of elastic/ingest-docs#113