S allius/issue217 (#229)

* move config.py into a sub directory cnf

* adapt unit test

* split config class

- use depency injection to get config

* increase test coverage

app/src/proxy.py

@@ -2,7 +2,7 @@ import asyncio
 import logging
 import json
 
-from config import Config
+from cnf.config import Config
 from mqtt import Mqtt
 from infos import Infos