Merge branch 'origin/fix/tutorial-exercise1f' into 'master'
[fix/tutorial-exercise1f] Exercise 1f makes more sense now The changing constitutive relations task in exercise 1 previously was about exchanging the EffToAbsLaw with a LinearMaterial law. It makes more sense to replace the RegularizedBrooksCorey. The description in the handbook was adapted accordingly. See merge request !248