Add convertor.py

[palak180]

Describe your changes (Mandatory)

Added a Binary to Decimal, Hexa and octal GUI convertor

Screenshots of your project output, whatever you have added. (Mandatory)

Checklist before requesting a review

• [x] I have performed a self-review of my code
• [x] If it is a new project, I have done thorough tests.

[shrey141102]

nice project 👍🏻