Port to Gnome 45

[muerwre]

Hello! Gnome 45 introduces new ES-like imports. I tried to port it myself, but ExtensionUtils also changed.

Here's the migration guide: https://gjs.guide/extensions/upgrading/gnome-shell-45.html

[René Coignard]

Hey @muerwre, I have added support for GNOME 45 in my fork

[muerwre]

Closed as duplicate of #17