Added test for ElectricityPrice

...ava/cz/muni/fi/pa165/core/metrics/MetricsServiceTest.java

...va/cz/muni/fi/pa165/electricityTarifMicroservice/App.java

...TarifMicroservice/electricityprices/ElectricityPrice.java

...service/electricityprices/ElectricityPriceController.java

...icroservice/electricityprices/ElectricityPriceMapper.java

...service/electricityprices/ElectricityPriceRepository.java

...croservice/electricityprices/ElectricityPriceService.java

...ervice/electricityprices/ElectricityPriceServiceImpl.java

...ctricityprices/NoElectricityPriceForCompanyException.java

...ityTarifMicroservice/electricityprices/ServiceConfig.java

...ce/electricityprices/dtos/ElectricityPriceGetFullDto.java

...ce/electricityprices/dtos/ElectricityPriceGetSlimDto.java

...rvice/electricityprices/dtos/ElectricityPricePostDto.java

...z/muni/fi/pa165/electricityTarifMicroservice/AppTest.java

...ice/electricityprices/ElectricityPriceControllerTest.java

...ervice/electricityprices/ElectricityPriceServiceTest.java

...i/pa165/microservice4/ElectricityPriceControllerTest.java