Add CODE_OF_CONDUCT.md

**Is your feature request related to a problem? Please describe.**
No CODE_OF_CONDUCT.md file is present.

**Describe the solution you'd like**
@ambujraj As a GSSOC participant I would like to add a CODE_OF_CONDUCT.md file in this project. Using [this]( https://www.contributor-covenant.org/version/1/4/code-of-conduct.html) as a reference.

**Additional context**
### Screenshots