dsr: Update documentation format

This updates the DSR model documentation according to #1139.

Additionally:

• Rephrase some explanations.
• Add 2 concept figures
• Delete an unnecessary header file
• Add reference to published paper

Important:

I tried something new here. Both the Attributes and Traces Sections now make use of Tables. The tables contain information as "Default" values of the attributes. In the case of the traces, I included the "callback signature" which becomes important when you want to connect to traces.

Edit: This Idea was dropped and instead we decided to use and improve the existing doxygen attribute and traces descriptions.

As usual, CHANGES.md will be modified before the final merge.