enum 추가, cors 설정 추가

src/main/java/com/kamco/cd/kamcoback/common/api/CommonController.java

@@ -9,7 +9,5 @@ import org.springframework.web.bind.annotation.RestController;
 public class CommonController {
 
   @GetMapping("/sheets/{id}")
-  public void getSheetList() {
-
-  }
+  public void getSheetList() {}
 }