Consignment and Customer Improvements

This release contains improvements to both Consignments and Customers in Fluent. Consignments can now store a list of attributes to enable the storage of custom information. Setting a timezone is now optional instead of mandatory when creating and updating a customer.

• Added extensibility to the `Consignment` entity by adding the standard `attributes` array field. This allows custom data fields and information, such as consignment costs, to be stored in the platform.
• `timezone` is now an optional field (previously required) on the `Customer` entity.