[patches] Remove script that generates patches for all exercises.

.create_all_patches.sh

-#!/bin/bash
-# SPDX-FileCopyrightInfo: Copyright © DuMux-Course contributors, see AUTHORS.md in root folder
-# SPDX-License-Identifier: GPL-3.0-or-later
-
-
-#This is to be executed at the root folder of dumux-course, no input arguments required. The script creates patches for all exercises stored in the exercise/ folder and with a name starting with exercise-*
-
-exerciseFolder=exercises/
-
-# Iterate over all subdirectories
-for exercise in $(find $exerciseFolder -maxdepth 1 -type d -name "exercise-*")
-do
-  #crop path to get exercise name
-  exerciseName=${exercise%/} # this removes the trailing slash of the path - % removes smallest suffix matching the given pattern
-  exerciseName=${exercise#exercises/} # this remove the leading exercises/ of the path - # removes the smallest prefix matching the given pattern
-
-  #check if the exercise-folder exists. Should always exist, as we iterate over them
-  if [ ! -d exercises/$exerciseName ]
-  then
-    echo
-    echo "exercises/$exerciseName does NOT exist. Terminating."
-    exit 1
-  fi
-
-  echo "Generating diff for $exerciseName. Storing the patch file into patches/$exerciseName/$exerciseName.patch"
-    diff -ruN $exercise exercises/solution/$exerciseName > .patches/$exerciseName/$exerciseName.patch
-
-done
-
-
-