Make return value for create/update API calls more consistent

[tw4l]

In some resource creation API endpoints we return the id for the object created, in others we don't. This could use a consistency pass.

@SuaYoo suggested returning the entire created object under a data key, which seems like a good idea to me!

@emma-sg suggested doing the same for PATCH requests so that we don't need to make follow-up requests from the frontend

[emma-sg]

It'd be great to do the same here for PATCH endpoints! @SuaYoo's suggestion sounds good to me.