[ADD] product_customer_code_picking module v.7.0

Moving the MP: https://code.launchpad.net/~agilebg/stock-logistic-flows/adding_product_customer_code_picking/+merge/202472
In fact if we had the new field in the pure tree view of stock moves, we would be temped to search on that field but we couldn't because the field is not stored and has no search method.

On the other hand, as @eLBati remarks, the field is not added to such a view, so we can consider that a missing feature and not a bug, which is OK by me.