New `Development workflow`, `How to contribute`, and `How to edit changelog` articles.
Co-authored-by: Wojtek Cichoń <wojciech.cichon@mudita.com>
Co-authored-by: Łukasz Anwajler <lukasz@anwajler.com>
Updated development process description to reflect recent arrangments
within the team. The discussion was mostly on how many commits should be
included in a single PR but eventually it led to a general review of a
development process.
Removed outdated diagram.
