Refactor LegacyApp to adhere to SOLID principles, KISS, YAGNI, DRY, and clean code

[sweep-ai[bot]]

Description

This PR refactors the LegacyApp to adhere to SOLID principles (Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion), KISS (Keep It Simple, Stupid), YAGNI (You Ain't Gonna Need It), DRY (Don't Repeat Yourself), and clean code practices.

Changes Made

• Created a new class ClientService to handle interactions with the ClientRepository.
• Created a new class UserCreditServiceWrapper to wrap the UserCreditServiceClient.
• Created an interface ICreditLimitCalculator and concrete implementations in the CreditLimitCalculators directory for each type of client to calculate the credit limit.
• Refactored the AddUser method in the UserService class to use the new classes and interfaces.
• Injected dependencies through the constructor or setter methods to adhere to the Dependency Inversion Principle.
• Removed the code that directly interacted with the ClientRepository and UserCreditServiceClient to improve testability and flexibility.

Checklist

• [ ] Follows SOLID principles, KISS, YAGNI, DRY, and clean code practices
• [ ] No breaking changes in the UserService class and its AddUser method
• [ ] Code is properly tested and all tests pass
• [ ] Documentation is updated, if necessary

Related Issue

Refactor to use SOLID principles, KISS, YAGNI and DRY as well as clean code

Fixes #1.

To checkout this PR branch, run the following command in your terminal:

git checkout sweep/refactor-legacy-app