Multi Inverter support

Grott supports input from more then 1 inverter.

If you have only 1 type basic inverter (TL-S, TL-X). Grott will work out of the box.

• For MQTT the device (PVSerial) is defined as "key" in the JSON Message
• if you want separate topics for each inverter you can add to the [MQTT] section of the grott.ini:
  
  mqttinverterintopic="True"
  
  or for docker
  
  -e gmqttinverterintopic="True"
  
  The inverterid will be added to the topic (e.g: energy/growatt/<your pvserial>)
• In influxdb a measure per device (pvserial) will be created.
• For support of multiple inverters with PVOutput see: Grott wiki: https://github.com/johanmeijer/grott/wiki/PVOutput.org-support

If you have different types of inverters and need different layouts to process the data

• add to the[system] section of grott.ini:
  invtypemap = {'<serial>': 'default', '<serial>': 'sph', '<serial>': 'default', '<serial>': 'sph'}
  
  or for docker
  
  -e ginvtypemap = "{'<pvserial1>': 'default', '<pvserial2>': 'sph', '<pvserial3>': 'default', '<pvserial4>': 'sph'}" for docker