Meter block value types

[marpi82]

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

solaredge-modbus-hass/custom_components/solaredge_modbus/sensor.py

Lines 352 to 353 in 49d1cd4

	#40211 Apparent Power
	m1_ac_va = data.decode_16bit_uint()

solaredge-modbus-hass/custom_components/solaredge_modbus/sensor.py

Lines 360 to 361 in 49d1cd4

	#40216 Reactive Power
	m1_ac_var = data.decode_16bit_uint()

solaredge-modbus-hass/custom_components/solaredge_modbus/sensor.py

Lines 368 to 369 in 49d1cd4

	#40221 Power Factor
	m1_ac_pf = data.decode_16bit_uint()

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)

solaredge-modbus-hass/custom_components/solaredge_modbus/__init__.py

Line 36 in 49d1cd4

client = ModbusClient(host, port=port, unit_id=1, auto_open=True)

[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. #22