Python: Document generator agent framework demo - #10184

### Motivation and Context

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We currently don't have a demo sample that shows how to use the agent
framework with multiple agents end-to-end. End-to-end means starting
from a task, designing the agents, and observing the agents.

### Description

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This PR adds a demo app that shows how to use the agent framework with
multiple agents to generate technical documents for Semantic Kernel.
This automation will greatly improve our productivity in creating more
contents.

This sample contains 3 agents, multiple plugins, and the necessary steps
to make the agents observable.

![image](https://github.com/user-attachments/assets/27fc0548-e052-481d-b9ad-845add5ec121)


> Note that this PR can be a starting point for discussion on how we can
further improve the agent framework.

### Contribution Checklist

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- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
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and the [pre-submission formatting
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raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄