'Virtual service IDs' in Service/PriceModel#POST and Service/PriceModel#PUT is returned in the response

[adamczykba]

Summary
Service/PriceModel#POST and Service/PriceModel#PUT endpoints works that ways, so they creates new 'virtual service' records while defining price model for customer.
To edit this price models it is needed to provide ID of this new object.
To gain user access to that value, let's make it so the requests would return proper ID in its response.

Details
N/A

Acceptance criteria

• Service/PriceModel#POST returns ID of 'virtual service' in the response
• Service/PriceModel#POST returns ID of 'virtual service' in the response

Additional context