update cnspec AWS doc

[misterpantz]

Description

• Remove the --option flag
• Add the --role flag
• Remove the instructions for scanning with an assumed role with an external ID (will add back when we have the ability again)

Related issue

none

Types of changes

• Functional documentation bug fix (i.e., broken link or some other busted behavior)
• New functional doc capabilities (i.e., filter search results)
• New content
• Revision to existing content
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist

• I have read the README document about contributing to this repo.
• I have tested my changes locally and there are no issues.
• All commits are signed.

[github-actions]

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[github-actions]

PREview has been updated at https://mondoo-pre-docs-333691036.storage.googleapis.com/docs/index.html