Update CONTRIBUTING.md

[Aman-Codes]

I am a GSSOC participant and I would like to update CONTRIBUTING.md file to include the following mentioned features

• How to clone the repository
• Adding reference to the original repository
• Updating local copy of repository
• Creating a new branch
• Pushing commits
• If possible we can also include some pictures in it for a better look
• It should also include the link to the pull request template, bug report and feature request template
• Update README.md to include the link of CONTRIBUTING.md

[Kuljeet-123]

@ambujraj Can I work on this issue??