Add Option for Sequential Naming while File Copying

[mrsudarshanrai]

I have been using the fs_crate for file copying in my project, and I've found it to be a valuable tool. However, I noticed that the crate currently provides options to either overwrite or skip existing files/folders, but it lacks the functionality to copy files with sequential naming.

This feature would be particularly useful in scenarios where users want to duplicate files to a destination directory but need to avoid overwriting existing files. The sequential naming option ensures that each copied file has a unique name without the risk of overwriting.