* [DOCS] Add ML categorization of messages
* [DOCS] Describe ML categorization_examples_limit property
* [DOCS] Updated ML categorization of messages
* [DOCS] Add links to ML categorization
Original commit: elastic/x-pack-elasticsearch@6403f6ce84
* [DOCS] Add role info to ML getting started docs
* [DOCS] Getting started with sample ML data
* [DOCS] Getting started with server-metrics sample data
Original commit: elastic/x-pack-elasticsearch@2f268f87b4
* [DOCS] First draft of ML getting started tutorial
* [DOCS] More ML getting started content
* [DOCS] Getting started content for data feeds
* [DOCS] Added ML getting started screenshot
Original commit: elastic/x-pack-elasticsearch@73174d27e8