Leaderboard issue#16

[sohammondal]

I have used the name Scoreboard for the component.

Features -

• The component renders only when there is at least 1 score saved in local storage.
• The best score is of color green
• The worst score is of the color red
• The board is sorted from best to worst

It renders like this -

Let me know if I need to make any changes.

[sohammondal]

I will update the code as per @itaditya 's comment. Please don't merge this.