Linux snap packages: Added Python GObject bindings
MR refers to discussion in #1409 (closed) @ted.gould
Enables extensions to use custom Gtk3 GUIs as it is already the case for the Windows, MacOS and Linux AppImage builds of Inkscape 1.x
Should also go into 1_0_x branch.
Closes #1409 (closed)
Edited by Jan Winkler