Add admin filtering to collection item lists

The admin filtering here is working as demoed.

The issue we saw with one item not showing up in the filter was related to the fact that it was not the canonical entity. The collection_item_path module is re-writing the link, without the class. I'll create a tiny branch/commit in that module so it will work with the filter. If, however, the class name changes here before merging, it will need to be changed there as well.