Ids from String to Long + findCertificateByUserId

...java/org/fuseri/model/dto/certificate/CertificateDto.java

...rg/fuseri/model/dto/certificate/CertificateSimpleDto.java

...ain/java/org/fuseri/model/dto/common/DomainObjectDto.java

.../src/main/java/org/fuseri/model/dto/course/CourseDto.java

...odel/src/main/java/org/fuseri/model/dto/user/UserDto.java

...c/main/java/org/fuseri/modulecertificate/Certificate.java

...seri/modulecertificate/service/CertificateController.java

...g/fuseri/modulecertificate/service/CertificateFacade.java

...g/fuseri/modulecertificate/service/CertificateMapper.java

...seri/modulecertificate/service/CertificateRepository.java

.../fuseri/modulecertificate/service/CertificateService.java

.../fuseri/modulecertificate/CertificateControllerTests.java