Implement Mock for Gitopia Client for Testing Purposes

[faza]

As part of our testing strategy, we need to create a mock implementation of the Gitopia client. This will allow us to simulate interactions with Gitopia services without making actual network calls, facilitating unit testing and ensuring our code behaves as expected under various scenarios.

Acceptance Criteria:

• The mock should cover all functionalities provided by the Gitopia client used in our project.
• It should allow for configuring responses to simulate different scenarios (success, failure, etc.).
• Include unit tests demonstrating the use of the mock to test a component that depends on the Gitopia client.