Add MLflow Guide/Demo notebook

[ronvoluted]

• Tidy up Dockerfile
• Add seaborn for my use, tidy dependency versions, add mlflow
• Add notebook showing how to use MLflow

Main thing is the notebook with MLflow demo. All you have to do is run pipenv install mlflow then pipenv run mlflow ui, and you'll be able to run the notebook as is to understand how MLflow works, then adapt it to your own notebook.

[rudecat]

Well done @ronvoluted in including the MLFlow. This will be super helpful!! :)