Add additional realistic example

[Mad-Kat]

As seen in #112 it would make sense to have an example (e.g. e-commerce store, a blog page...) with the app router that utilizes more next.js specific features than our current example that is a playground for different CSS use-cases.

[rvetere]

how about the official next tutorial about app router? https://nextjs.org/learn
it's very good structured and maybe we could speed-up that task by taking parts of it

[Mad-Kat]

Definitely an option :) We're open for any examples that show how next-yak can be used in various scenarios