Merge branch 'main' into 'language-school-user'

# Conflicts:
#   application/model/src/main/java/org/fuseri/model/dto/certificate/CertificateDto.java
#   application/model/src/main/java/org/fuseri/model/dto/course/CourseDto.java
#   application/model/src/main/java/org/fuseri/model/dto/course/LanguageTypeDto.java
#   application/model/src/main/java/org/fuseri/model/dto/lecture/LectureCreateDto.java
#   application/module-certificate/src/main/java/org/fuseri/modulecertificate/service/CertificateController.java
#   application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/course/Course.java
#   application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/course/CourseController.java
#   application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/course/ProficiencyLevel.java
#   application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/lecture/Lecture.java
#   application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/lecture/LectureController.java
#   application/module-language-school/src/test/java/org/fuseri/modulelanguageschool/course/CourseTest.java
#   application/module-language-school/src/test/java/org/fuseri/modulelanguageschool/lecture/LectureTest.java