Improvements in QuantityBreakType entity definition and services

Required improvements;

• All is good with entity definition.
• Add CRUD services using entity-auto. Make sure PK is optional while create service, so that can be generated from OFBiz sequence generator.
• Do related changes if any occurrence found for direct create/update/delete of this entity, and replace them with crud services implemented.
• As no status/from date/thru date exists in entity, so nothing needs to be taken care while deleting the records from service.