[WAL-1842] Extend OrderItemSerializer with offering_type and plan_description fields.
[WAL-1842] Extend OrderItemSerializer with offering_type and plan_description fields.

opennode/waldur-mastermind,opennode/nodeconductor-assembly-waldur,opennode/waldur-mastermind,opennode/nodeconductor-assembly-waldur,opennode/waldur-mastermind,opennode/nodeconductor-assembly-waldur,opennode/waldur-mastermind