Render pcolormesh plots as SVG files with rasterization

[redeboer]

pcolormesh plots like the intensity and the uncertainty distributions as well as scatter plots are currently exported as PNG, because SVG becomes too bloated. But by enabling rasterization, the plot region with the distributions becomes a PNG, whereas the axis are still vector graphics. In fact, using dpi with rasterization (i.e., when exporting as PNG) results in a reduction of the quality on the edges on each pixel in the pcolormesh.
https://matplotlib.org/3.10.0/gallery/misc/rasterization_demo.html