only recommend users install our components as peerDependencies if they are making a library

[chee]

we updated --save to --save-peer here: https://github.com/Financial-Times/origami/pull/604

but actually we need to explain that if the user is implementing a LIBRARY that other computer programmes will depend on that they should save Origami deps as peerDependencies and if they are implement an APPLICATION that they should save Origami deps as direct dependencies.

It's more important that we do this bit quickly than that we add the documentation explaining why libs should use peers and apps should use deps, but we should also add that doc and link to it from this section of the tut