Add delete (and retire?) for program states in the workflow

The GUI has no method for removing a state from a workflow in a program. There is only the capability for making a state initial or terminal.

There should be a way to delete states.

What to do when you have already used a state for a patient? Should the system only allow the state to be retired (ie. no longer show up on the patient dashboard as a choice)? If the state cannot be removed (deleted or retired), there should be a user-friendly message to explain the reason.