Improve Holdings Template Management

The current system of holdings template management is complicated and inefficient. Libraries should be able to set up item templates that can be assigned to specific users or workstations. If the template is edited, everyone who has been assigned that template would automatically have the current version. Each user or workstation would have only the templates they currently need — if the library adds a new format or a particular user is no longer responsible for adding Adult Mysteries, the holdings templates can be added or removed from their settings.