Disable Hibernate cascading for Encounter.orders and Obs.order

We should (probably) turn off cascading for Encounter.orders and explicitly set the one for Obs.order to none
EncounterServiceImpl.saveEncounter needs to manually call some method in OrderService in order to save all new Orders. (Old orders aren't allowed to be edited.)
It should avoid duplicating code
Make sure to test the case where you add a new REVISE or DC order, and ensure this cascades to setting the date stopped on the original order
Also, ensure that if you void an encounter (and this voids all Orders in that Encounter), this is properly cascaded