Adjustments can now be open/closed/finalized
- Add a state machine to adjustments with states open, closed, finalized
- Once an adjustment is finalized, it cannot be changed, but an
  adjustment can toggle between open/closed as needed
- Update Admin UI to allow users to toggle an adjustment's state
Show the correct item total on order details page

[Fixes #2376]
Fixing tiny typo

Fixes #2377