action.hold_request should store user and workstation ids related to the cancellation

[Michele Morgan]

When a hold is cancelled, there is no record of the user (patron or staff user) that cancelled the hold, or the workstation where the cancellation was performed. It would be useful to have two additional fields in action.hold_request, one storing the id of the user that performed the cancellation and one storing the workstation where it was performed.

These fields should be included as column choices in Holds grids.

[Ryan Eby (aadl-ubuntu)]

I'd suggest that an auditor.hold_request would be a good solution similar to the copy and usr auditors. The lack of auditing has made tracking bugs down a little harder where the auditors for the other 2 tables has helped a lot.