Documentation of features and how to configure

[grossmann]

General

• Module version: latest dev
• Magento version: 2.3.2
• PHP version: 7.2.19

Issue description

There is not documentation about the features this module implements, how they are implemented, and how to configure the individual features.

On the Magento 1 version there was a detailed feature description (see https://github.com/firegento/firegento-magesetup/blob/development/docs/features/features.md), not sure if this are all valid for the Magento 2 version as well.

A "competitor" module lists some basic information (see http://doc.magenerds.com/germanlaw/) which gives a much better understanding what functionality to get.