Add new widget classes and update README for widgets protection

[aisuvro]

Hi,
This PR adds new widget classes to enhance functionality and updates the README to reflect changes related to widget protection.

[what-the-diff]

PR Summary 🚀

• Revamped Readme Examples! 📖
  Our README.md just got a cool upgrade! It now provides easy-to-follow examples on how to use our fresh TableWidget, ChartWidget, and StatsOverviewWidget from the Coolsam\Modules. This will help you to understand how to implement and use these nifty widgets in a snap. 🌟

• New and Improved ChartWidget 📈
  Check out our new addition: src/ChartWidget.php! This new file defines an enhanced ChartWidget that not only chart creation easier but also maintains the user access control. Based on the solid foundation of Filament\Widgets\ChartWidget, our elevated version expands its capabilities and makes it even more powerful while keeping it secure. 🛡️

• Power-Packed StatsOverviewWidget 📊
  We're happy to introduce our brand new src/StatsOverviewWidget.php file that defines an advanced StatsOverviewWidget class. Rooted in Filament\Widgets\StatsOverviewWidget, our new class gives it a boost by incorporating access control aspects. Now gather data-driven statistics effortlessly with superior security checks! 👏

All these changes cumulatively work to enhance your experience while using our modules and provide robust functionality alongside intricate access control. And we're just warming up, the best is yet to come! 🌈✨