Patron requests should have their own cancel reasons

Right now it looks as though the cancel reasons for Acq patron requests is the same list as the normal cancel reasons that we use for line items. I think these should be two different distinct lists.

The reasons to cancel a user request can definitely vary from reasons why a purchase might be canceled. Adding those potential reasons to the cancel reasons lists means that the list could get much larger and be more unwieldy for when it's being used in purchase orders as well as in requests.

As we're considering using this in PINES, I'm also currently envisioning that this interface would be widely used by Circ staff while talking with a patron. So Circ staff don't know that the book is delayed, or canceled because of the ISBN or whathaveyou. So all of those cancel reasons are useless to them.

So I think that user requests should get an additional table(s) to have their own distinct cancel reason list.