Feature/add python bindings

.gitlab-ci.yml

 ---
 variables:
-  # DUNECI_TOOLCHAIN:   gcc-7-17
   DUNE_CONTROL_PATH:  /duneci/modules:$CI_PROJECT_DIR
   DUNE_PY_DIR:        /duneci/modules/dune-py
-  DUNECI_PARALLEL:    6
+  # adding this actually leads to the test failure seen in the core modules
+  # DUNECI_PARALLEL:    6  # don't know why this is required here but not for core modules - magic?
   PYTHONPATH:         "/duneci/modules/dune-common/build-cmake/python:/duneci/modules/dune-geometry/build-cmake/python:/duneci/modules/dune-grid/build-cmake/python:/duneci/modules/dune-istl/build-cmake/python:/duneci/modules/dune-alugrid/build-cmake/python:/duneci/modules/dune-fem/build-cmake/python:$CI_PROJECT_DIR/build-cmake/python"
 
 before_script: