Add integration pipeline
To make output fields and the split algorithm work, the order of the code in creationfunctions.py was changed. This led to a nonworking entropic LBM because the add_entropy_condition in entropic.py is not able to deal with the additional Assignments. The error occurred in the integration pipeline with waLBerla.
In this MR the integration pipeline was added to lbmpy to make sure that the waLBerla integration works as it should and the order in creationfunctions.py was changed again to make sure all test cases are working.