feat: add initial dashbot package implementation

- Created a new Dashbot package with core functionalities.
- Implemented Dashbot window model and notifier for state management.
- Added UI components including Dashbot default page and home page.
- Integrated routing for Dashbot with initial routes defined.
- Included assets for Dashbot icons and set up pubspec.yaml.
- Added tests for Dashbot window notifier to ensure functionality.
- Established a basic README and CHANGELOG for the package.

packages/dashbot/lib/dashbot.dart

@@ -0,0 +1,3 @@
+export 'dashbot_dashboard.dart';
+export 'core/providers/dashbot_window_notifier.dart';
+export 'core/utils/utils.dart';