Add "Optimization" to what-if-tool for analysis

[tsereno]

I am just submitting this as an idea for new functionality. Use blackbox (i.e. scikit-optimize minimize function) to display the minimum or maximum prediction value for regression or the max probability of predicted class for classification, for specified bounds or global. Every use case isn't optimization, but identifying an optimal value and it's predictors can be really useful for predictive model analysis.