refactor: mv footer from pages to components folder

Author: jane1107

src/pages/Footer.tsx renamed to src/components/common/Footer.tsx

@@ -1,8 +1,7 @@
 import EditPwPage from './EditPwPage';
-import Footer from './Footer';
 import JoinPage from './JoinPage';
 import Loading from './Loading';
 import LoginPage from './LoginPage';
 import { NotFound } from './Notfound';
 
-export { EditPwPage, Footer, JoinPage, Loading, LoginPage, NotFound };
+export { EditPwPage, JoinPage, Loading, LoginPage, NotFound };