Add 404 page

[harshmangalam]

• Create 404 page
• Add button for Home page navigation
• Use https://undraw.co/illustrations to download free 404 page svg illustration
• Add title and description

[sathithyayogi]

Hi, shall i take this ?

[harshmangalam]

Sure sathithya, start contribution from 1st of October so that your contribution can be considered as valid hactoberfest PR.