Also aligned books, shelves and chapters to return description content
and some relations (where not breaking API) in create/update responses
also so that information can be seen direct from that input in a
request.
API docs and tests not yet updated to match.
- Fixed page editor default focus not working as expected due to
misnamed attribute.
- Added owned_by to relevant areas of the API including the docs.
- Made book relation on page accessible even if deleted since it could cause an issue on views, such as audit trail, when the relation is accessed when the book is deleted.
- Tweaked how books are passed on update to prevent unassignment if
parameter is not provided.
- Added books to validation so they show in docs.
- Added request/response examples.
- Added tests to cover.
- Added child book info to shelf info.
Review of #1908
