Migrate class components to functional components

[itaditya]

All components except Testimonials.js just have a render method. They don't use any special stuff which class components provide. Since there is a transpilation cost associated with class components, we should use function components instead.

Note- I'm not talking about adding hooks in the project. The only place where a hook would be useful is Testimonials.js but it is fine its current state. I'm just talking about other components which don't need hooks

[praveenweb]

@itaditya - Makes sense. Would you like to work on this?

[itaditya]

@praveenweb since I have already got three PRs merged, I'm eligible for Hasura Hacktoberfest t-shirt. So let's give this opportunity to someone else. If no one picks it up in the next two days, I'll work on it.

Also do I need to do anything else regarding the Hasura Hacktoberfest?

[deadcoder0904]

I'll tackle this one :)

[deadcoder0904]

Sent a PR #70