Delete C++ directory

[the1Riddle]

Description

cpp won't be updated anymore, and I will focus on C#, SQL, and bash if any.

Fixes #(issue_no)

• Issue_no: <insert your issue no here>
• Not applicable

Checklist:

• My code beats 50% + of the users, will 💙 to hear this.
• I have named my files and folder according to this project's guidelines.
• My code follows the style guidelines of this project and is up to date with the current trends.
• I have commented on my code, particularly in hard-to-understand areas and included the time complexity O(n).
• I have created a helpful and easy to understand README.md especially when you create a new directory.
• My changes do not produce any warnings.

Happy leetcoding 💌