Description

Added Vertical Order Traversal of Binary Tree to C++ directory

Checklist:

[ ] I have read the contribution guidelines before making this PR.
[ ] My code follows the style guidelines of this project
[ ] I have performed a self-review of my own code
[ ] I have commented in my code, particularly in hard-to-understand areas
[ ] I have made corresponding changes to the documentation (Language folder or any other readme instructed to)
[ ] My changes generates no new warnings
[ ] I have added tests that prove my fix is effective or that my feature works