feat: move Settings out of Files into its own searchable app with categories

scripts/install_apps.sh

@@ -47,6 +47,7 @@ APPS=(
     "screenshot|apps/scalable/gnome-screenshot.svg"
     "texteditor|apps/scalable/accessories-text-editor.svg"
     "files|apps/scalable/system-file-manager.svg"
+    "settings|categories/scalable/preferences-system.svg"
     "mandelbrot|apps/scalable/applications-science.svg"
 )