Improved regularizations in quadruped problem + example used ANYmal robot

This PR makes a tiny modification in the formulation of the quadrupedal problem, just changes the weight for the state and control regularization. This modification is done in both: c++ and Python versions.

Additionally, the quadrupedal-gait example uses the ANYmal robot since this is more interesting for our partners.

@wxmerkt you might be interesting in trying these values. With I modified version of the box-script, I achieved convergence within 35 iterations. I could push this code if you want it.