Refactoring

Here are some of the improvements

• Improved error handling: I added proper error handling using log.Fatalf and fmt.Errorf to provide meaningful error messages when encountering errors.
• Removed unnecessary imports: I removed the unused imports to keep the code clean.
• Restructured code: I restructured the code to improve readability and maintainability.
• Added proper log file handling: The log file is opened, closed, and set as the log output within the if condition where the log file name is provided.
• Utilized os.IsNotExist: Instead of using errors.Is(err, os.ErrNotExist), I used os.IsNotExist(err) to check if a file exists.
• Improved struct tags: I added mapstructure tags to the Configurations struct fields to indicate the corresponding keys in the YAML configuration file.

See #4