Make script flow visualisations work regardless of flow pattern (size).

Currently the script flow works hardcoded for vertical size of 1 and 2, as explained [here](https://stackoverflow.com/questions/75110767/position-of-images-as-nodes-in-networkx-plot), however for screen flows with 3 vertical screens, the rendering does not work.

I tried changing the figure size and the vertical positions of the 3 images, however that did not result in a vertical spacing between the 3 vertical screens. Even when changing the aspect ratio of the image. An option could perhaps be to:
- increase the figure size, and/or aspect ratio based on the screen image size and nr of vertical levels.
- Lower the screen image size in the `piesize = 0.4 # this is the image size` parameter.
such that the images become relatively smaller in the figure, but that the figure becomes larger, yielding the same DPI per image.