Oh good idead, didn't know you could do that! I thought it had to be added in Roll20 or other VTTs after the upload. I think I put a light source on one level, for the stove or something, but it was just for the visual effect.
As I said, I'm not sure I'll work more on this, but feel free to take the file, add it and then share your upgraded map! If not, it will be on my future to do list haha.