[task] (get/delete) /withdrawal API 요청 : 회원탈퇴

### ISSUE
- Group: `server`
-Type: `feature`
-Detail: 회원탈퇴. method `delete` 알아보고 적합하면 `delete` 사용하기

### TODO
1. [x] db에서 해당 유저 삭제
2. [x] 해당 유저와 관련된 모든 정보 삭제

### Estimated time
>Pick one

### `1h`

Start by locating the server's existing member and withdrawal API routes, then inspect how account data and related information are stored and removed. Confirm whether DELETE is appropriate for the withdrawal endpoint. Done means the endpoint removes the user and all related information as described in the TODO.

Written by the indexing model from the issue text.