Manual section metadata

Manuals need to expose their section metadata to the manuals front end in the form of an array of titles, slugs and summary.

The `ArtefactPresenter` is already in a fairly bad state so an `#edition` method has been added to the presenters in an effort to make them composable. The new `ManualArtefactPresenter` utilises this composability and no material changes were made to the `ArtefactPresenter`.