application-properties

Create a simple yet powerful configuration management tool for Python applications using the 'application-properties' package. This tool will allow developers to easily manage their application settings, such as database connection strings, API keys, logging levels, and more. It should provide a user-friendly interface for both setting up initial configurations and updating existing ones without needing to modify code directly. Here are the key steps and features you'll implement:

1. **Setup Initial Configuration**: Develop a script that reads a predefined set of properties from a YAML file and stores them into the application's property store using the 'application-properties' package.
2. **Access Properties**: Write functions within your application to dynamically access these properties during runtime, ensuring that changes made to the YAML file are reflected immediately.
3. **User Interface**: Create a basic command-line interface (CLI) that allows users to view current settings, update specific properties, and even add new ones if needed.
4. **Security Considerations**: Ensure sensitive information like API keys and passwords are stored securely and not exposed in plain text within the YAML file or output.
5. **Documentation & Testing**: Provide comprehensive documentation on how to use your configuration management tool and include unit tests to verify its functionality.

The goal is to streamline the process of managing application configurations while keeping the solution simple and efficient. Use the 'application-properties' package to handle the underlying storage and retrieval of these properties, focusing instead on building an intuitive CLI for interaction.