Major rewrite of the communication protocol.
Besides existing Goodwe's Modbus/RTU over UDP, standard Modbus/TCP is now supported too (e.g. Wifi/LAN kit 20).
272 Fix max value of grid_export_limit - either 10000, or 2* inverter rated power (if known).
HA 115837 Fix N/A energy/power values on DT inverters.
Implement async_update so settings values can be reloaded by homeassistant.update_entity service