Add more agent factory examples

What does this merge request do and why?

This MR adds more agent factory examples:

• hello world
• hello world with the structured output
• issue manager with tools and summary

How to set up and validate locally

1. Check out to this merge request's branch.
2. Install dependencies.

   poetry run install

3. Check the existing commands ELI5 provides:

   poetry run eli5 agent-factory --help

Merge request checklist

• Tests added for new functionality. If not, please raise an issue to follow up.
• Documentation added/updated, if needed.