Import web image: open clipart (ocal) source missing on Linux

Steps to Replicate

1. Open Inkscape
2. File > Import web image
3. View list of sources in the top right dropdown

What happened?

• ocal is missing
• In these cases, it looks like from bs4 import BeautifulSoup fails.

What should have happened?

ocal listed

I think we need to:

1. Add it to our list of documented dependencies
2. Add it to our Windows dependencies (this would have to be solved in inkscape/inkscape of course), presumably it is https://packages.msys2.org/base/mingw-w64-python-beautifulsoup4 fixed in !4858 (merged) for 1.3, !4911 (merged) for 1.2.2
3. Add it to the ppa's recommended dependencies (if it isn't already there)

And for anyone on Linux experiencing this (appimage, ppa, personal build, or part of your package manager), I believe pip3 install beautifulsoup4 should fix the problem.

Version Info

• Fails on Inkscape 1.2 on Windows 10 (per inkscape_user report https://chat.inkscape.org/channel/inkscape_user?msg=yyd4cap2E5biLwTyw by Don.McFarland), and through wine
• Fails on Arch (personal build of 1.3-dev)
• Succeeds on mac (as reported by Polygon)
• Succeeds on Linux Mint 20 (as reported by me)