Refactor legacy project to use SOLID principles, KISS, YAGNI, DRY, and clean code

[sweep-ai[bot]]

Description

This PR refactors the legacy project to adhere to SOLID principles (Single Responsibility, Open-Closed, Liskov Substitution, Interface Segregation, and 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 IClientRepository interface with a GetById method.
• Created IUserCreditServiceWrapper interface with a GetCreditLimit method.
• Created IUserDataAccess interface with an AddUser method.
• Implemented IClientRepository interface in ClientRepository class.
• Created UserCreditServiceWrapper class that implements IUserCreditServiceWrapper interface and wraps UserCreditServiceClient.
• Implemented IUserDataAccess interface in UserDataAccess class.
• Refactored UserService class to use the newly created interfaces.
• Broke the AddUser method into smaller, more manageable methods.
• Used constructor injection to get the dependencies.

Checklist

• [x] Created IClientRepository interface
• [x] Created IUserCreditServiceWrapper interface
• [x] Created IUserDataAccess interface
• [x] Implemented IClientRepository interface in ClientRepository class
• [x] Created UserCreditServiceWrapper class
• [x] Implemented IUserDataAccess interface in UserDataAccess class
• [x] Refactored UserService class
• [x] Broke AddUser method into smaller methods
• [x] Used constructor injection for dependencies

Additional Notes

• The IUserCreditService and IUserCreditServiceChannel interfaces and the UserCreditServiceClient class are generated code and were not modified.
• The code within LegacyApp.Consumer was not changed as per the request.

Please review and merge this PR. Thank you!

Fixes #1.

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

git checkout sweep/refactor-legacy-project