add defaults for automatic sensors

[230delphi]

WARNING (MainThread) [homeassistant.helpers.template] Template warning: 'int' got invalid input 'unknown' when rendering template '{{states('sensor.alphaess2_totalsolar')|int + states('sensor.alphaess2_feedin_grid_power_in')|int + states('sensor.alphaess2_batteryrq_load_out')|int}}' but no default was specified. Currently 'int' will return '0', however this template will fail to render in Home Assistant core 2022.1