Unifying .rst file's markup

[tommylenz]

When writing .rst files for our docs, it doesn't really matter what markup you use, e.g. a headline will be a headline no matter what kind of styling you use (refering to the sphinx docs):

##########
Headline 1
##########

Headline 2
==========

To make it easier to create and edit docs, we agreed on a markup-standart as follows:

Doc title
=========

Headline
--------

Subheadline
***********

Now, all docs need to be sighted and edited to fit the standart.