Install icon to the app_id location

This is so that the desktop files picks it up correctly.

Thanks, @WhyNotHugo and @jbeich.

resources/meson.build

@@ -37,7 +37,10 @@ if scour.found()
       install: true,
       install_dir: icondir)
 else
-install_data(icon, install_dir: icondir)
+  install_data(icon,
+    rename: '@0@.svg'.format(meson.project_name()),
+    install_dir: icondir
+  )
 endif
 
 install_data(