[test][python] memory issue
requested to merge kienle_at_mechbau.uni-stuttgart.de/dune-fufem:remotes/origin/test/dunepythonmemorytest into master
- add duneypthonmemorytest to show memory issue
- when calling a converted python function with arguments in a loop it leads to memory leakage
- while calling a function without arguments it seems to be fine