Add one additional workflow category

I saw the request closed to let people add their own categories. This request is for you to add a single, static category for us to use. Hopefully, this will make sense. 

If I want to measure flow efficiency (how much of the total duration of a piece of work has been spent queuing versus working) then I need to have workflow states marked as inactive/waiting/queueing (whatever word most makes sense). There is no current category to use to mark states as queueing states unless you mark them as "To Do". Right now, I recommend that people do just that... use the category "To Do" to represent all the waiting.

However, I don't know what functionality that will be impacted negatively if that is meant to show the wait BEFORE the work has ever "started".