[UI] Putting all sections of home-page into index.html and making uniformity in design

[Waishnav]

As fellow contributors have made each home page section, the design might look non-uniform. So to avoid this UI issue, we need to make the home page look uniform according to the Figma design.

Also, make sure to follow the following constraints.

• gallery section includes images.json and it includes the src link of each image (relative link), so after changing its directory it won't work. so fixed that issue.
• navbar is not mobile-responsive. consider making it mobile responsive.

[ChaudharyRaman]

I would like to work on this issue.