Implement warehouse/lot pricing updates and configurator performance fixes

migrations/020_add_only_in_stock_to_configurations.sql

@@ -0,0 +1,3 @@
+-- Add only_in_stock toggle to configuration settings persisted in MariaDB.
+ALTER TABLE qt_configurations
+    ADD COLUMN IF NOT EXISTS only_in_stock BOOLEAN NOT NULL DEFAULT FALSE AFTER disable_price_refresh;