Meter block value types

[marpi82]

I have noticed that these values isn't correct (they should be "signed int" no "unsigned"):

https://github.com/erikarenhill/solaredge-modbus-hass/blob/49d1cd4864abc1c9306f5a63e0c2ddf04fd4f4a9/custom_components/solaredge_modbus/sensor.py#L352-L353 https://github.com/erikarenhill/solaredge-modbus-hass/blob/49d1cd4864abc1c9306f5a63e0c2ddf04fd4f4a9/custom_components/solaredge_modbus/sensor.py#L360-L361 https://github.com/erikarenhill/solaredge-modbus-hass/blob/49d1cd4864abc1c9306f5a63e0c2ddf04fd4f4a9/custom_components/solaredge_modbus/sensor.py#L368-L369

I have also suggestion about configuration becouse most of people have configured modbus unit as 1 (first device), but I have as second. Could You made a little modification to configure these from hass

I say about these line (unit_id) https://github.com/erikarenhill/solaredge-modbus-hass/blob/49d1cd4864abc1c9306f5a63e0c2ddf04fd4f4a9/custom_components/solaredge_modbus/init.py#L36

[erikarenhill]

@marpi82 should be fixed with this PR, do you have the possibility to test this pr/branch to verify functionality before I merge? I don't have a separate meter to do this on my own. https://github.com/erikarenhill/solaredge-modbus-hass/pull/22