Add usages of Next 13 layouts where applicable

[joshirohit100]

NextJS 12.3 now provides different way to create route (app directory) and layout.
old pages directory will be supported for backward and legacy purpose.

As that will be the new way, we should support / add that for new / fresh setup

Reference - https://nextjs.org/blog/next-12-3#new-router-and-layouts-update

[lauriii]

Once #155 has been resolved, we should experiment with the Next 13 layouts. We should try to convert the current layout into the new layout system in Next 13: https://nextjs.org/blog/next-13#new-app-directory-beta. We may want to refrain from merging that until the layout system has been marked as stable. We could alternatively ship an additional starter template that uses the layouts out of the box.