Refactor backend MVC (#2)

* docs(requirements.txt):升级fastapi、uvicorn版本

* refactor(user)：重构用户router、service

* ref: role list api

* doc: 1

* refactor(backend): mvc ref

backend/schemas/__init__.py

@@ -1,4 +1 @@
-from schemas.common import *
-from schemas.menu import *
-from schemas.role import *
-from schemas.user import *
+