역할: REST API 엔드포인트를 제공하는 컨트롤러 클래스
getAllServers(HttpServletRequest request)GET /api/serversList<ServerResponse>getServer(@PathVariable Long id, HttpServletRequest request)GET /api/servers/{id}ServerResponse 또는 404 Not FoundcreateServer(@Valid @RequestBody CreateServerRequest request)POST /api/servers@Valid를 통한 입력값 검증ServerResponse