Workspace-specific guake on Wayland

The feature to have a [guake per workspace](https://github.com/Guake/guake/issues/32) does currently [only work on X11](https://github.com/Guake/guake/pull/1584). If issued [an entry on FeatHub](https://feathub.com/Guake/guake/+76).

A unified approach could be to use the [Extended Window Manager Hints](https://en.wikipedia.org/wiki/Extended_Window_Manager_Hints). There is even a [Python library](https://github.com/parkouss/pyewmh) that implements an interface. This MWE yields the correct workspace on Wayland:

```py
from ewmh import EWMH
ewmh = EWMH()

desktop = ewmh.getCurrentDesktop()
ewmh.display.flush()

print("desktop: ", desktop)
```