Adding a custom 404 page

[Aman-G-upta]

Currently, the website does not have a custom 404 error page. When users navigate to a non-existent URL, they are either presented with a default server error page or a blank page. A custom 404 page would improve the user experience by guiding users back to relevant parts of the site instead of leaving them with an error.

Design a 404 page with the following elements:
A friendly message to inform the user that the page is not found.
A link back to the homepage or main sections of the website.

Please assign me under this issue @PriyaGhosal

[github-actions]

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