Add multiple scale support

Now only one scale can be applied for each aesthetic. We can't fix it for all, bur for some of them it's possible with new lets-plot feature:
https://nbviewer.org/github/JetBrains/lets-plot-kotlin/blob/master/docs/examples/jupyter-notebooks/f-4.3.0/multiple_color_scales.ipynb

Start with the linked multiple_color_scales.ipynb example to understand the referenced lets-plot capability and which aesthetics support multiple scales. Done means adding multiple-scale support for the applicable aesthetics in Kandy, with behavior matching the example.

Written by the indexing model from the issue text.