Augment Prototype DecisionBoundary Viz with metrics

[ndanielsen]

Add labels with metrics such as recall, precision, tpr and etc to the DecisionBoundaryVisualizer

As seen in as the visualizations in this blog post:

https://medium.com/towards-data-science/what-metrics-should-we-use-on-imbalanced-data-set-precision-recall-roc-e2e79252aeba

Example from the blog post: