Better controller handling

[pieter-pon]

Handle also typed objects, so you can return e.g. a model, and you dont have to explode it body: { ...product }
Also check the docblocks, what is optional and what required, are all types correct, can it more detailed
(e.g. nor just array or object, add more details how it looks like, like an array of strings, or the fields of the object)

When an empty body is send (undefined / null), is this valid? Should we return a 5xx?