Feat/Sorting a singly linked list using C language

[Nihhaar0002]

This contribution adds a complete singly linked list implementation in C with useful operations:

Insert a node at the beginning, at a specific position, or at the end.
Delete a node from the beginning, from a specific position, or from the end.
Display the list, search for a value, and find maximum and minimum elements.
Sort the list in ascending order.
Reverse the list.
Count the total number of nodes.

The code is organized under the data_structures/ folder and follows a clear structure for easy understanding and reuse.
This implementation will help beginners understand linked list operations and provides a reference for common linked list algorithms in C.