AST-1030 Move ResultSteps to different file
Moving ResultStep paves the way for moving NullStep to a different file, which is needed using OutputStep as a base class of NullStep. This work was split of !728 (merged) .
Moving ResultStep paves the way for moving NullStep to a different file, which is needed using OutputStep as a base class of NullStep. This work was split of !728 (merged) .