Removes all tight_layout calls

Matplotlib offers constrained layouts:

https://matplotlib.org/stable/tutorials/intermediate/constrainedlayout_guide.html

which performs better than tight layouts:

https://github.com/matplotlib/cheatsheets/issues/30#issuecomment-655594205

At the same time, tight layout is known to trigger certain bugs. For example:

https://github.com/matplotlib/ipympl/issues/335

Here we remove all call to tight_layout in the toolbox. @carinanc @mercurio

doc/index.rst

@@ -19,6 +19,21 @@ where in this example 2780 is the proposal number. After this and refreshing the
 browser, a new kernel named ``SCS Toolbox (p002780)`` is available and should
 be used to run jupyter notebooks on the Maxwell Jupyter hub.
 
+Figures setup: enabling matplotlib constrained layout
++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+To get the best looking figures generated by the SCS Toolbox, you
+need to enable the experimental constrained_layout_ solver in matplotlib. This
+is done in jupyter notebook with adding at the start the following lines:
+
+.. code:: python
+
+   import matplotlib.pyplot as plt
+   plt.rcParams['figure.constrained_layout.use'] = True
+
+.. _constrained_layout: https://matplotlib.org/stable/tutorials/intermediate/constrainedlayout_guide.html
+
+
 Alternative: Manual ToolBox Installation
 ++++++++++++++++++++++++++++++++++++++++