Improve documentation for Quantiles in the User Guide

[exalate-issue-sync]

http://docs.h2o.ai/h2o/latest-stable/h2o-docs/data-science/common.html

Currently, the entire Quantiles topic is a single note, followed by the early stopping sections. It will be nice to improve that topic a little and pull the early stopping topic into its own separate file.

For Quantiles, just above the note, specify what the quantiles function does, which is that it retrieves and displays quantiles for H2O parsed data, along with the parameters that can be specified. (The R documentation has better a better description for the parameters, I think.) Then add R and Python examples after the note.

[h2o-ops]

JIRA Issue Migration Info

Jira Issue: PUBDEV-7500
Assignee: hannah.tillman
Reporter: Angela Bartz
State: Resolved
Fix Version: 3.30.0.3
Attachments: N/A
Development PRs: Available

Linked PRs from JIRA

#4573