Notes about caching pages with a CSRF Form

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | no
| Applies to    | all
| Fixed tickets | #1216
I think this component splitting deserves a nice book entry in the components section.

What do you want to do with this cookbook? 
Maybe we can remove this note now and add a link when this piece of doc is added, or perhaps we can rephrase it some way?