NR Control: Agent Control GA doc updates (text + images)

[dhmsgit]

• Update Agent Control docs for K8s GA (callouts, wording, links)
• Fix Fluent Bit install steps in Log Collector Management
• Clean up statements in Agent Types
• Clarify Setup, Monitoring, Reinstrumentation, Troubleshooting, Upgrading topics
• Replace architecture diagram and AC install button image with slightly better ones
• Resolve merge with latest develop
• Fix assorted typos/grammar

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[github-actions]

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