Add Stack Datastructure with user input

[Bhakti23-CE]

###Summary: This PR introduces a new Python program that implements a stack class with various operations, allowing user interaction.

###Features added: Stack class with methods:

• push: Pushes an item onto stack.
• pop: Pop the top item of the stack and handle empty stack case.
• peek: Returns the top element of stack without removing and checks if stack is empty.
• is_empty: Checks if the stack is empty.
• size: Returns the current size of the stack.
• print_stack: Prints the elements present in stack.

Main Function:

• Provides menu with options to perform stack operations.
• Handles invalid inputs.