Document status: Only get/set via model functions

[jvwong]

The Document model contains accessors for status get and set. These should be utilized, and we should not set status directly. This is so any logic associate with status changes are always enacted.

There are three places where status is altered and should be checked:

• Admin UI
• Editor submit tasks
• Server api document endpoint

[jvwong]

Directly setting document.status( astatus ) only happens in the admin