Show active date instead of create date in holdings grid

When viewing a record in the staff client, the holdings grid includes a column for displaying an item's create date. In my opinion, it would be more useful to show the active date instead.

Create date indicates when the item record was created. For libraries that use acquisitions or creates records for on-order items, the item record may be created long before the item is actually in-hand. An item's active date is populated when the item is checked in. So from the perspective of someone looking at the holdings grid, the item is arguably not meaningfully part of the library's collection prior to the active date.

Sitka has a local customization to display active date instead of create date. I'll share a version of that change momentarily.

(This issue affects Evergreen master and previous versions of EG at least as far back as 2.6.)