GTIN with leading zeros (RTC-45396)

Leading zeros in GTIN are trimmed when importing items to offer by Excel, JSON or API request. Items would now be matched properly, because Item Service does not allow leading zeros in GTIN as well. Additionally, wrapping spaces are trimmed when importing by GTIN or External Item Number.

Promotion in many store groups (RTC-43027)

It is possible to select multiple stores, teams or profiles when creating a promotion in user interface. Dropdown is replaced by multiselect field. In 'Promotions', 'Promotion offers', 'Items in promotions' grids, such promotion has correct level in 'Available in' column and 'Store group code/name' are empty.
For now, ordinary price for items in offer groups are always taken from first store group of promotion (first one displayed in promotion details).
User with permission 'Manage promotions' limited to store/store group level, can edit promotion specific level, only when having permission to all stores/store groups of the promotion.