Aziz Emir ~ Enhance Bank System with Modular Structure, User Management, and Transfer Functionality

[AzizEmir]

1. Modular Structure: Refactored the codebase to use modular structures for Bank, User, and Transaction components.
2. PaymentProcessor Enhancements: Implemented the add_bank method for the PaymentProcessor struct to manage multiple banks.
3. User Transfer Function: Added a transfer method to the User struct to handle fund transfers between users.
4. Example Usage: Added a usage example of the transfer function in the main function to demonstrate its functionality.
5. Bank Improvements: Introduced the new method with a fee parameter and an add_user method to the Bank struct for user management.
6. Clone Trait Derivation: Implemented the Clone trait for Bank, Transaction, and User structs to enable cloning of these objects.
7. Main Refactor: Updated the main function to utilize new Bank methods, including user listing and management functionalities.

[erklyn]

Eline saglik, main'e merge etmiyecegimiz icin boyle birakiyoruz :D

[AzizEmir]

Teşekkürler 😃