legend height cannot be adjusted #318

Hi,
The legend of figures is higher than the figure, which makes it ugly. It would be nice if users can adjust colorbar's colormap, height, width, position, vmax, vmin. All this features are provided by scanpy and squidpy, while I don't find them in spatialdata.
Here is a figure:

And this is another figure from https://spatialdata.scverse.org/en/latest/tutorials/notebooks/notebooks/examples/technology_xenium.html