[Enhance][Bug fix] Improve setting file & ...

- Fix a small bug that `best30` of API cannot have scores whose songs are not in database
- At present the setting file can be a module or a file with some of options
- Limiter can have multiple rules together now

latest version/api/api_auth.py

@@ -2,10 +2,10 @@ from functools import wraps
 from traceback import format_exc
 
 from core.api_user import APIUser
+from core.config_manager import Config
 from core.error import ArcError, NoAccess, PostError
 from core.sql import Connect
 from flask import current_app
-from setting import Config
 
 from .api_code import error_return