FreeCAD Sketch Export

This extension is tested to work with FreeCAD up to version 0.21. On Linux we can install that older version by sudo apt install freecad==0.21

Newer versions 1.X require some updates of this extension, because the library changes are large and might be bundled within AppImage on Linux. The FreeCAD python modules can be ripped off by ./<appimage-name> --appimage-extract.