Squashed commit

Fixed recipe ingredient costs/calories calculation when having different QUs and when only_check_single_unit_in_stock is set (fixes #2529)
Added a new column "Product picture" on /products (closes #2640)
Fixed partly opening stock entries stock_id handling (fixes #2391)

migrations/0242.php

@@ -0,0 +1,22 @@
+<?php
+
+// This is executed inside DatabaseMigrationService class/context
+
+// Assign a new stock_id to all opened stock entries where there is also an unopened one with the same stock_id
+$db = $this->getDatabaseService();
+
+$sql = 'SELECT s1.id
+FROM stock s1
+WHERE IFNULL(s1.open, 0) = 1
+ AND EXISTS (
+	SELECT 1
+	FROM stock s2
+	WHERE s2.stock_id = s1.stock_id
+		AND IFNULL(s2.open, 0) = 0
+	)';
+
+$rows = $db->ExecuteDbQuery($sql)->fetchAll(\PDO::FETCH_OBJ);
+foreach ($rows as $row)
+{
+	$db->ExecuteDbStatement('UPDATE stock SET stock_id = \'' . uniqid() . '\' WHERE id = ' . $row->id);
+}