Extent the configuration for Smart Meter and Batteries

[s-allius]

To support devices other than inverters, we have several approaches. At the moment, the configuration in config.toml always starts with the keyword inverters. Now we can:

1. simply add the new device types under inverters as well. Disadvantage, we do not check the grammar for the individual devices, as this depends on the data entered (e.g. serial number)
2. add separate keywords like, smart_meters, batteries. Then we could customize the grammar for each type specifically.

I would prefer the second approach.

@mime24 : What do you think? How can we map this for the add-on?

Example:

[inverters."R170000000000001"]  # must start with R17, Y17 or Y47
node_id = 'inv1'                 # MQTT replacement for inverters serial number  
suggested_area = 'Roof'  # suggested installation place for home-assistant

[batteries."4100000000000001"]  # must start with 410
monitor_sn = 2070233888
node_id = 'batt1'                    # MQTT replacement for battery serial number  
suggested_area = 'Garage'  # suggested installation place for home-assistant

[mime24]

separate keywords sounds defiantly more meaningful. It should be possible to adjust the config.yaml accordingly. but I'm not available for the next 8 days to create a test config.