Add CityMapper

core/src/main/java/cz/muni/fi/pa165/core/mapper/CityMapper.java

+package cz.muni.fi.pa165.core.mapper;
+
+import cz.muni.fi.pa165.core.data.domain.City;
+import cz.muni.fi.pa165.core.model.CityDto;
+import cz.muni.fi.pa165.core.model.NewCityDtoRequest;
+import org.mapstruct.Mapper;
+
+@Mapper(componentModel = "spring")
+public interface CityMapper {
+
+    City toEntity(CityDto cityDto);
+
+    City toEntityFromNewRequest(NewCityDtoRequest newCityDtoRequest);
+
+    CityDto toDto(City city);
+}