Jupyter: Export static image so pdf conversion works

[timkpaine]

plotly/plotly.py#1623

[texodus]

This is a bit tricky for the core lib as we still rely heavily on SVG for both the Highcharts and D3FC plugins. We could try rendering the SVG to canvas via canvg or similar but should probably restrict its inclusion to the Jupyterlab plugin as it is a quite large lib.

[RandomFractals]

saving svg and converting it to png doesn't require any extra canvg libs. I can't believe you and d3fc maintainers are still 'exploring' this simple JS add-on option. start here :) https://observablehq.com/@mbostock/saving-svg

[RandomFractals]

related: #646 (comment)

[timkpaine]

closing as this is out of scope for now, we can revisit in the future. Given that perspective-python now supports going to and from dataframe/arrow, in the context of NBConvert it is relatively easy to just swap out perspective's grid and plotting for pandas native rendering and matplotlib, respectively.