Add CONTRIBUTING.md file

[baranwalayush]

• Added the CONTRIBUTING.md file to better help the new contributors and adhere to the standard coding guidelines.

[draeger]

I left a few suggestions for improvement. Thanks for preparing that!

[tyzerrr]

@baranwalayush Basically, LGTM.
But maybe, this file is a little bit huge size.
CONTRINUTING.md is an entry point for new contributors, so this file should be shortened as much as possible.
This repo, official golang github repo is a great example for you.

[NeumannArthur]

LGTM

[baranwalayush]

@tyzerrr Thank you for the suggestion! In the case of Golang, they have a separate webpage for contribution guidelines where they are redirecting from the contributing.md page, which is not true in our case. Besides that, I believe that there is nothing overwhelming in this file and a new contributor can easily read and understand the guidelines.