Add new 'state' to States for managing post_'COMPLETED' state editing

[thorwolpert]

In NameX's tiny state model, moving a Request to INPROGRESS locks out other users, allows for certain security checks, etc.

Post COMPLETED status editing is required for certain business requirements, and as such we should add a new state to support the transition of that (or similar mechanism).

[katiemcgoff]

Also: don't let someone else RESET/RE-OPEN if NR is in the editing state.