feat(core): add a demonstration script to generate a graphviz pdf graph from a Dialogue

[scrowland]

Proposed Changes

Demonstrate how to draw a simple graph visualisation of a Dialogue's state graph using the Graphviz package.

Linked Issues

[if applicable, add links to issues resolved by this PR]

Types of changes

What type of change does this pull request make (put an x in the boxes that apply)?

• [ ] Bug fix (non-breaking change that fixes an issue).
• [x] New feature added (non-breaking change that adds functionality).
• [ ] Breaking change (fix or feature that would cause existing functionality to stop working as expected).
• [ ] Documentation update.
• [ ] Something else (e.g., tests, scripts, example, deployment, infrastructure).

Checklist

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• [ ] I have read the CONTRIBUTING guide
• [ ] Checks and tests pass locally

If applicable

• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have checked that code coverage does not decrease
• [ ] I have added/updated the documentation

Further comments

[if this is a relatively large or complex change, kick off a discussion by explaining why you chose the solution you did, what alternatives you considered, etc...]

[Archento]

Thanks for the contribution!

There is definitely a need for visualisation of the Dialogues and we'll be providing a native way for that in the near future. Currently we try to keep the dependencies to a minimum especially if packages rely on external tools to be present but it's a good start regardless!

I'll leave this PR open as a reference and until this topic has been resolved.