Update to gtk4-rs 0.2
Updates gtk4-rs to 0.2 and gtk3-rs to 0.14.
- The help-overlay.ui was used for the GTK 4 version
- The python script was added an
e.g
for repository and app id - GTK 4 runtime was set to master, 40's version of gtk4 is too old and developers should target master most of the time