Implement retry mechanism for deletion errors

[DubyaDude]

This PR was entirely made using Github Copilot Workspace.
Some small optimizations need to be done before merging.

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Closes #16

Implements a retry mechanism for file and directory deletion operations, enhancing error handling and user interaction.

• Error Handling Enhancements

  • Adds TryDeleteDirectoryWithRetry and TryDeleteFileWithRetry methods in Utils.cs to attempt deletion with a retry mechanism. These methods loop until the operation succeeds, the user decides to skip, or the user quits the program.
  • Incorporates user prompts within the retry mechanism, offering options to retry, skip, or quit upon encountering deletion errors.

• Integration with Existing Code

  • Utilizes the new retry mechanism methods in BoothBatchDownloader.cs for deleting directories and files. This ensures that if a deletion fails, the user is prompted with options to handle the error gracefully.
  • Modifies directory and file deletion logic to use the retry mechanism, improving robustness against locked files or other deletion errors.

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