Enhancement: Customizable file system oterator implementation

[arilou]

This patch introduces the capability to implement custom iterators for file system traversal. This flexibility is particularly beneficial for applications requiring specialized handling of file systems, such as iterating over archive formats (e.g., tar, zip) or employing alternative traversal logic. For instance, this feature addresses community requests for functionality to avoid following symbolic links during file system operations.

With this update, developers can tailor file system iteration to better meet their specific application needs.