[Cleanup] Remove attachments

src/main/java/com/example/demo/config/SwaggerConfig.java

src/main/java/com/example/demo/domain/Attachment.java

src/main/java/com/example/demo/domain/Task.java

src/main/java/com/example/demo/dto/AttachmentDto.java

src/main/java/com/example/demo/dto/TaskDto.java

src/main/java/com/example/demo/dto/TaskUpdateDto.java

...a/com/example/demo/dto/input/GameDefinitionCreateDto.java

src/main/java/com/example/demo/mapper/BeanMapper.java