Update iop documentation

[ehelms]

Why are you introducing these changes? (Problem description, related links)

The IOP documentation covered the basics (enabling, service list, databases, config) but was missing significant architectural detail that exists in the source code. Operators and developers had to read Ansible roles to understand data flow, deployment ordering, FDW setup, the CVE map downloader, systemd integration, and backup behavior.

What are the changes introduced in this pull request?

• Add data flow section with end-to-end pipeline narrative and Kafka topic table
• Add deployment order section documenting the 16-step orchestration from iop_core
• Add smart proxy registration details (OAuth, relay config)
• Add systemd integration section (foreman.target, oneshot/timer patterns, timer table)
• Add foreign data wrapper (FDW) section with iop_fdw role explanation and ASCII diagram
• Add CVE map downloader section with online/offline modes and reposync trigger
• Add VMAAS-Katello integration section explaining repo list sync
• Add backup and restore section listing the 5 database dumps
• Add container inventory summary table (~23 running + 3 oneshot/timer)
• Expand services table with inventory sub-containers and vulnerability container breakdown
• Add inventory frontend (was missing from the diagram and frontend assets section)
• Update configuration table with OAuth consumer key/secret variables
• Expand certificates table with all IOP cert paths including CVE map downloader and VMAAS
• Note Kafka's separate image, image pre-pull, and engine console.redhat.com hosts mapping

How to test this pull request

Steps to reproduce:

• Read docs/iop.md and verify the new sections are accurate against the source roles in src/roles/iop_*
• Verify the deployment order matches src/roles/iop_core/tasks/main.yaml
• Verify the Kafka topics match src/roles/iop_kafka/files/kafka/init
• Verify the FDW description matches src/roles/iop_fdw/tasks/main.yaml
• Verify the CVE map downloader description matches src/roles/iop_cvemap_downloader/

Checklist

• Tests added/updated (if applicable)
• Documentation updated (if applicable)

[ehelms]

@vkrizan Would you mind reviewing? This was generated by AI based on the source code.