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/tests/test_proxy.py

@@ -9,7 +9,7 @@ from singleton import Singleton
 from proxy import Proxy
 from mqtt import Mqtt
 from gen3plus.solarman_v5 import SolarmanV5
-from config import Config
+from cnf.config import Config
 
 
 pytest_plugins = ('pytest_asyncio',)