Product handbook: Change of style

[gunbra32]

I request changing the style of the handbook from alabaster to sphinxdoc before publishing it on the public webpage, i.e. before milestone 2 of the project. Reason: looks much cleaner and fits much better with a science/tech project, in my opinon.

To get an idea about the available styles you may want to have look here:
http://www.sphinx-doc.org/en/stable/theming.html