Order Service allows duplicate orders

The Order Service is currently allowing duplicate orders, which it should not. For example, you can order "Triomune-40" multiple times for the same patient. You can also order "SERUM CREATININE" tests multiple times for the same patient. The Order Service should not allow two concurrent orders of the same orderable (i.e., concept+drug for drug orders, concept for all other types of orders).

TODO:

• OrderService.saveOrder needs to check if an order exists for the same orderable, i.e drug for drug orders and concept for other orders, if an existing order is found for the same orderable it should fail