Refactor tutorial to use dataclass for configuration

[Aatman09]

Resolves #107

Reference
This implementation is based on the following tutorial:
JAX Machine Translation Tutorial

Changes made

• Added dataclass-based configuration for improved clarity and structure
• Enhanced the tutorial with additional Markdown explanations for better readability

Notes

• Key–value (KV) caching has been left out

Checklist

• I have read the Contribution Guidelines and used pre-commit hooks to format this commit.
• I have added all the necessary unit tests for my change. (run_model.py for model usage, test_outputs.py and/or model_validation_colab.ipynb for quality).
• (If using an LLM) I have carefully reviewed and removed all superfluous comments or unneeded, commented-out code. Only necessary and functional code remains.
• I have signed the Contributor License Agreement (CLA).