Many part of this commit were made by Carlos
Garnacho <carlosg@gnome.org>
WIP wacom: Port to GTK4
Lots of stuff missing and probably broken.
wacom: Port CcDrawingArea input to gestures
We have a handy GtkGestureStylus to use here, which avoids direct
handling of GdkEvents.
wacom: Update current stylus tracking to GtkGestureStylus
Use the ::proximity signal to notice when we are being hovered with
a tablet stylus, and look up the tool from there.
Same dog, different collar. The UI has been ported 1:1 to GTK+, using
GtkBuilder, CSS and event controllers fairly reduced the amount of code
needed for this.
It also allows us to stop initializing clutter-gtk across the several
executables.
