DOC: update docs and tutorials to 2.0

[mtsokol]

Hi @j-ittner!

In this PR I will submit all updated tutorials and docs, here's todo list:

• [x] Classification Tutorial: Prediabetes update
• [x] auxiliary Diabetes getting stared update
• [x] Introductory Tutorial: Incident risk of drilling operations update
• [x] Generating Standard Scikit-learn Classifier Performance Summaries update
• [x] sphinx documentation update

Sequential PR: Need to merge #317 first.