Drop python3-sphinxcontrib.svg2pdfconverter dependency
requested to merge wip/adalessandro/drop-python3-sphinxcontrib.svg2pdfconverter into apertis/v2022dev2
Package python3-sphinxcontrib.svg2pdfconverter is not available in Apertis, let's drop it to cut down the dependency chain. This build dep is used to build documentation and will fail silently.