Add a how to page

[nobodyczcz]

A "how to page" which describes what information is available on the tracker and how to access different types of data:

• costs
  • levels of information extraction
• plans
• description on how to read the fields of the data table, what does the gap mean, what is considered optimal ... ...

[dharabor]

Renamed. I think what we're talking about is an overview page, with some feature descriptions and examples.