Added salutation field on Customer

Added a new optional field on customer resource to store information about the salutation of the customers. Added two new cart discount functions that help specify whether the given predicate should match for at least one or for all line items in the cart.

• [API] Customer has a new optional field salutation that can be set during creation of the customer or changed afterwards by new update action setSalutation.
• [API] Two new Cart discount predicate functions lineItemExists and forAllLineItems were added.