Upgrade lookbook gem to v1.0

What does this MR do and why?

Lookbook had its 1.0 release a few days ago 🎉 This version comes with many improvements on the UI but is backwards-compatible. So no changes to our component previews are required.

This version also contains my PR that disables CSP in RAILS_ENV=development. With this we don't need the class_eval in the initializer anymore and can clean that up 🚮

Screenshots or screen recordings

How to set up and validate locally

• bundle && gdk restart rails-web
• Browse http://gdk.test:3000/rails/lookbook

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.