Allow disabling the drawing of hulls in figures #76
Description
In generate_figure_polis() in data_presenter(), we always draw the hull. It would be nice to be able to disable this, and just have the colored points as indication of groups.
Example of no hulls:
https://github.com/polis-community/red-dwarf/blob/50fb97db8a718ca1bfe3c5d2a1048867562d161c/docs/notebooks/experiment-pca-pacmap-localmap-comparison.ipynb
Hulls (only option now)
Without
