Update of Scaling tutorial

[JacobAdamsen]

The following have been updated in the Scaling and Personalizing tutorial:

• Added code snippets to enable Test of models
• Updated all images
• Cleaned up the folders and files so it corresponds to the lesson structure
• Made other minor updates

[melund]

@pgalibarov You better also take a look a the build tutorial, and confirm that things still look as you like. Otherwise, we can also merge this, and you can look at the final results, and come with suggestions for changes.