final squash

tiny refactoring
````java
@RequestMapping(method= RequestMethod.POST, consumes = "multipart/form-data")
    public ResponseEntity<String> postImageUpload(@RequestParam("name") String ID,
                                                  @RequestParam("file") MultipartFile file) throws IOException, JcrException {
        if (file.isEmpty()) {
            return new ResponseEntity<>("You failed to upload " +
                    ID + " because the file was empty.", HttpStatus.BAD_REQUEST);
        }
        String contentType = file.getContentType();
        if(!isSupportedFormat(contentType)) {
            return new ResponseEntity<>("You failed to upload " +
                        ID + "-image" + " because the file has incorrect type: " + file.getContentType(), HttpStatus.BAD_REQUEST);
        }
        applicantID = ID + "-image";
        imageFile = new ImageFile(applicantID, file.getOriginalFilename(),file.getContentType(), file.getBytes());
        responce = imageService.postImage(imageFile);
        return new ResponseEntity<>(responce + applicantID, HttpStatus.OK);
    }

    private boolean isSupportedFormat(String format){
        return  format.equals("image/gif") ||
                format.equals("image/jpeg") ||
                format.equals("image/png");
    }
````