Updated documentation includes configuring logout and setting up MATLAB as an interactive app

The documentation regarding configuring logout has been made more prominent. See the Authentication section and in particular the third step in the overview to configure logout.

We also added a tutorial on adding MATLAB, similar to how we offer the Jupyter and RStudio tutorials. This includes examples of how to configure XFCE, Mate, and Fluxbox as window managers for GUI apps like MATLAB and Paraview.