Admin opens records VERY slowly at Item level

[ZacharyLesser]

This is new since the Links issue was fixed (or at that time if that caused by that)

[apjanco]

Item admin was bogged down by many lookups to populate the dropdowns. As suggested here, I added raw_id_fields for ('title_page_company_filter','stationer_printer','stationer_publisher','stationer_bookseller','variant_links','in_collection','also_in_collection_link','collection_contains', 'independent_playbook_link')

This interface is less intuitive, as the user needs to update the object id directly, but is significantly faster.

[ZacharyLesser]

Let's revert this because the fix makes it too non-intuitive for us to work easily with Items. We'll see if this can be resolved in some other way later.