Develop ATC documentation and host it on Read The Docs

[yugoslavskiy]

Problem

Our readme is huge, hard to read, hard to understand.
There are no informational pages for our entities (like Response Actions), rather than those short descriptions from README.
There are a few blind spots that should be clarified, i.e:

• how to properly manage Detection Rules severity
• how to prioritize the implementation, what to do first
• how all of these supposed to work together

Solution

We need to:

• store only important information in the README
• develop detailed documentation and refer to it in the README

Implementation

Develop documentation using mkdocs and store it on Read The Docs.
After that, develop a simplified version of README.