ADD (linux) workspace support

[allanlaal]

use case:

I have hundreds of windows open across 36 workspaces with ~600 tabs open in them
I sometimes need to get a list of all tabs grouped by window on a certain workspace, dump those back into my todolist, then close those windows to free up the workspace

Workspaces are also called Desktops (in wmctrl) and Spaces (in MacOS)