Add delete buttons to the item holds list

[jim]

On the item holds page, there is no way to remove a hold:

To delete a hold, you have to click on the member name, then go to their holds list, and find the right hold, and then remove it.

Now that we can disable holds for an individual item, we'll want to be able to more easily clean up holds that aren't needed. Plus, it would be nice to streamline common hold workflows for items where holds are still being used (which is most items).

• Add a small button to each hold that, when clicked, shows a confirmation dialog. If the user accepts the dialog, the hold should be removed.
• We could use a button with a little trash can icon on it to keep the buttons small. Feather icons, the set we use, has two to choose from.