Add random forest algorithm

[kylecorry31]

https://en.wikipedia.org/wiki/Random_forest

https://towardsdatascience.com/understanding-random-forest-58381e0602d2

https://towardsdatascience.com/an-implementation-and-explanation-of-the-random-forest-in-python-77bf308a9b76

https://towardsdatascience.com/random-forests-and-decision-trees-from-scratch-in-python-3e4fa5ae4249