Use cookbook to explain some nu_scripts

[kubouch]

Currently, the cookbook is rather underwhelming. The idea of the cookbook is to show practical recipes and how-to guides with explanations. One idea how to add more content is to take some nice script from nu_scripts and go through it in detail in a cookbook page. This has two benefits:

1. Enhanced in-depth documentation for scripts in nu_scripts
2. More cookbook content

Of course, we can think of other scripts to add to nu_scripts that would be interesting to cover in the cookbook.