#PLAT-3128 Introduce method to retrieve child manager and extract structure methods into separate services
Created by: ITDarkUFO
- Moved logic from UsersAppService to StructureAppService
- Moved logic from IUsersService and UsersService to IStructureService and StructureService
- Created StaffUserDto to encapsulate managers info
- Implemented GetUserClientManager in IStaffService
- Added GetChildManager methods to StructureAppService and StructureController