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/gen3plus/solarman_v5.py

@@ -6,7 +6,7 @@ from datetime import datetime
 
 from async_ifc import AsyncIfc
 from messages import hex_dump_memory, Message, State
-from config import Config
+from cnf.config import Config
 from modbus import Modbus
 from gen3plus.infos_g3p import InfosG3P
 from infos import Register, Fmt