Basic Singly Linked List Implementation in C

Create a new file named 'linked_list.c' to implement a basic Singly Linked List.

The implementation should define a struct Node and include at least two functions:

1. insert_at_beginning(int data): Inserts a new node at the head of the list.
2. display_list(): Prints all elements in the linked list.

The main function should demonstrate inserting 3 or more elements and then displaying the final list.