Merge remote-tracking branch 'origin/M2-user' into M2

# Conflicts:
#	application/model/src/main/java/org/fuseri/model/dto/user/UserDto.java
#	application/module-certificate/src/test/java/org/fuseri/modulecertificate/CertificateControllerTests.java
#	application/module-certificate/src/test/java/org/fuseri/modulecertificate/CertificateFacadeTests.java
#	application/module-certificate/src/test/java/org/fuseri/modulecertificate/CertificateMapperTests.java
#	application/module-certificate/src/test/java/org/fuseri/modulecertificate/CertificateServiceTests.java
#	application/module-exercise/src/main/java/org/fuseri/moduleexercise/exercise/ExerciseFacade.java
#	application/module-language-school/src/test/java/org/fuseri/modulelanguageschool/user/UserControllerTest.java