Doc: Figure out how to include SVG graphics in PDF output

[dbaston]

Feature description

The current documentation build process is not able to include SVG images. In ReadTheDocs builds, the images are simply omitted. In CMake builds, where warnings are treated as errors, including an SVG image causes the build to fail. For the survey results page, which contains many SVG images, I omitted the entire page from the LaTeX build in fbcdb64b22e278b8099cfca6b3b3b52b4bd340b8. However, as we add more graphics to the docs, we may want to include SVGs in material that should be in the PDF.

Additional context

Resolving this may be as simple as enabling sphinx.ext.imgconverter. https://www.sphinx-doc.org/en/master/usage/extensions/imgconverter.html . It would be good to compare this to other options such as https://github.com/missinglinkelectronics/sphinxcontrib-svg2pdfconverter