Added Contributing guidelines

[Supratim30]

Added the required contributing guideline. Please check and merge the PR with hacktoberfest-accepted label.
Thank you.

[zeel-pathak]

@Supratim30, The contributing guide looks a little monotonous, You can refer to this https://mozillascience.github.io/working-open-workshop/contributing/ It will be great if we can have crystal clear Guidelines, So it would be easy for newcomers to adapt to the Environment and can you also add a general Code of Conduct may be a separate markdown for that as of now.

[Supratim30]

Hey @zeel-pathak added a general code of conduct. The guidelines follows all the criteria from the link provided. Please look into it and let me know.
Thank you

[zeel-pathak]

I do not see any specific changes other than you added spaces after every paragraph, you can add more of your creativity to it, It seems you have just cut and pasted the guidelines from somewhere else.

You can refer to the above-shared link and know what a contribution markdown should contain and as per this project, you can create one with your creativity.