Refactored the code to be more efficient and easy to read. added some more options in the preferences added about page in the preferences

1. You have `this.openPreferences()` in the entry point. Please remove line 115 `extension.js` and use that instead: [Port Guide 45: Extension Utils](https://gjs.guide/extensions/upgrading/gnome-shell-45.html#extensionutils) 2. Please rename `perfs.js` to `settings.js` so it's not confusing for the reviewers. since you cannot load `prefs.js` into the shell process (line 12 `extension.js`). Also, don't use `Preferences` for the class name that is going to be imported in `extension.js` for the same reason. 3. You already have `this.getSettings()` in the entry point (line 9 `perfs.js`): [Port Guide 45: Extension Utils](https://gjs.guide/extensions/upgrading/gnome-shell-45.html#extensionutils) 4. Please remove unnecessary files: - `screenshot.png` - `Makefile` If you need any help with your extension you can ask us on: - [GNOME Extensions Matrix Channel](https://matrix.to/#/#extensions:gnome.org) - IRC Bridge: irc://irc.gimpnet.org/shell-extensions