Improve documentation

[MatousJobanek]

Issue Overview

This issue is to gather all important things that should be improved in our documentation.

• developer guide - #289

• gather information/parts that are related. eg:

  • if I want to know something about strategy, I need to go through there parts: the description of the strategy, file configuration desc. and reference card.
  • if I want to know how to use one config parameter, there is no one place that would contain everything important (param name, system property, description, default value).

Please add more items in the comments.