Implement BST using C#

- Study and R&D Binary Search Tree (BST)
- Implement BST using C#
- Insert, update and delete bst
- Traverse BST using pre order, in order and post order traversal

Reference:
- https://www.geeksforgeeks.org/construct-bst-from-given-preorder-traversa/
- Computer programming - data structures and algorithm (part -03) - Tamim shahriar suvin