Make Email model changeable from config

[Jacobtims]

This pull request makes the Email model configurable via the config/filament-email.php config file.
This allows users to override the Email model used by the package.

[Jacobtims]

Fixes #30

[what-the-diff]

🎉 PR Summary 🎉

Hello there! Here's a simple summation of the changes we've made:

• Configurable Email Model Update: 💌 Now, the RickDBCN\FilamentEmail\Models\Email model can be found in your config/filament-email.php config file. This increases flexibility on how and where this model is utilized across your project.
• Factory and Resource Class Fun: 🏭 The EmailFactory and EmailResource classes underwent changes for better functioning! These classes now dynamically pull the Email model from our config file or if not found, they'll rely on our default RickDBCN\FilamentEmail\Models\Email 😊.
• Record Variable Update: 📝 For ease, the $record parameter found in EmailResource class was updated to a generic type. Same for the resend method!
• Logger Class Enhancements: 📚 The FilamentEmailLogger class has a new 'model' variable which fetches the model from the config (or defaults to RickDBCN\FilamentEmail\Models\Email as a failsafe). This plays a key role when creating new instances.
• ResendMail and Test Updates: 📬🧪 The $email parameter in ResendMail class is now of a generic type — ensuing better adaptability. Plus, the EmailModelTest file got spicier with a beforeEach hook to fetch our model. This makes the test cases even smarter!

All in all, these changes flex up elements of autonomy and efficiency in our code — ensuring it dances smoothly to the rhythm of your project's needs. Enjoy the updated harmony! 🎶🤩

[RickDBCN]

Looks good to me! Thanks! :)