Merge branch 'feature/python-main-file' into 'master'

.gitignore

.gitlab-ci/default.yml

.pylintrc

cmake.opts

dumux/python/CMakeLists.txt

dumux/python/assembly/CMakeLists.txt

dumux/python/assembly/fvassembler.hh

dumux/python/common/boundarytypes.hh

dumux/python/common/fvproblem.hh

dumux/python/common/timeloop.hh

dumux/python/common/volumevariables.hh

dumux/python/discretization/gridgeometry.hh

dumux/python/discretization/gridvariables.hh

dumux/python/io/CMakeLists.txt

dumux/python/io/vtkoutputmodule.hh

dumux/python/material/CMakeLists.txt

dumux/python/material/components/CMakeLists.txt

dumux/python/material/components/component.hh

dumux/python/material/fluidsystems/CMakeLists.txt

dumux/python/material/fluidsystems/fluidsystem.hh