Barcode should reference item_link rather than item

[Chris-Petty]

Is your feature request related to a problem? Please describe 👀

For item merging support, all FKs to item should go through item_link as an intermediate. Barcode.item_id got missed it seems!

open-msupply/server/repository/src/db_diesel/barcode_row.rs

Lines 22 to 23 in e3f1c1a

	joinable!(barcode -> item (item_id));
	joinable!(barcode -> invoice_line (id));

Describe the solution you'd like 🎁

Update to go through item_link. See stock_line.item_link_id for an example, and related PRs for similar changes needed.

Describe alternatives you've considered 💭

Additional context 💌

Moneyworks Jobcode 🧰