Shortly after the window-list extension was added, it gained a
workspace switcher based on the workspace indicator extension.
Duplicating the code wasn't a big issue while the switcher was
a simple menu, but since it gained previews with a fair bit of
custom styling, syncing changes between the two extensions has
become tedious, in particular as the two copies have slightly
diverged over time.
In order to allow the two copies to converge again, the indicator
code needs to be separate from the extension boilerplate, so
split out the code into a separate module.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/307>
Florian Müllner
19877302a6