WIP order identities

Allow multiple identities for orders, typically used for storing external identifications, such as an backend (ERP) order id.
Processed comments, added removeIdentity method, adjusted OrderSpec
[PromotionBundle] The collection form type uses the new CollectionExtension
[PromotionBundle] Collection type refactoring
[PromotionBundle] Behat fixes
Add cascade to product options field (doctrine mapping)

Change cascade from all to persist
Merge pull request #2247 from steffenbrem/fix-options-persist

[Product][Easy] Add cascade to product options field (doctrine mapping)
Merge pull request #2239 from aRn0D/promotion

[PromotionBundle] The collection form type uses the new CollectionExtension
Sylius i18n
Merge pull request #2101 from gonzalovilaseca/gv-product-translation-prezent

 [WIP] [RFC] Product translation (Prezent)
Remove outdated specs, update composer.lock
Fix and merge search scenarios, run them on travis
Do not access the database during cache clearing
Fix typo in RouteProvider
Fix fixtures and 5.3 compatibility
Rework product features, elimiate some scenarios and simplify
Allow setting coupon expiration from backend
List coupon expiration
Optimize the memory usage a bit, clean up features
Merge pull request #2263 from umpirsky/feature/add-coupon-expires-at-field

Allow setting coupon expiration from backend