Fixed severity posed by sonarqube

[PALASH2201]

What problem does this PR solve?

This PR addresses the security concern of hardcoding MongoDB credentials directly into the codebase. Storing credentials in the code can expose sensitive information, especially when working in a shared or open-source repository.

The .env file has been introduced to securely store MongoDB credentials, which are then fetched within the application. Additionally, the test cases have been modified accordingly to ensure that they work seamlessly with this new environment-based credential setup.

Close #2865

[PALASH2201]

@iluwatar Can you add mongo db secrets in this repo So that they can be accessed in github action

[stale[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.

[github-actions[bot]]

This PR is stale because it has been open 60 days with no activity.