Implement changes proposed by @s-hadinger review.
* Use 0-255 range in settings
* Apply gamma correction from xdrv_light & use changuintscale helper fn (as per pwm light routine)
- Bump version 8.3.1.2
- Change Energy JSON Total field from ``"Total":[33.736,11.717,16.978]`` to ``"Total":33.736,"TotalTariff":[11.717,16.978]``
- Change Energy JSON ExportActive field from ``"ExportActive":[33.736,11.717,16.978]`` to ``"ExportActive":33.736,"ExportActiveTariff":[11.717,16.978]``
- Add Three Phase Export Active Energy to SDM630 driver
* Extra setting & command to set - allows masking of pwm mode. Use case is for leds attached to buttons for seeing at night; this way user can combine both pwm and digital leds (i.e. pwm for the button leds but non-button status leds can stay on/off).
* When setting PWM values, updates all the LEDs (instant response). Uses led_power values.
* If LEDLINK not set, but LED1 is, LED1 is the status led. When turning on/off, setledlink uses digitalwrite (which does not respect the new pwm operation). In this case only, we will use the setledpoweridx instead of digitalwrite - costly (every 250ms this runs), but edge case / legacy. Allows more intuitive operation - if we blink an LED with the max and min PWM limits, we'd expect it to respect these. In this case, blink will also now update the led_power status, which keeps this accurate e.g. if ledpower 1 cmnd was sent, then blink occurred, led_state would read a 1 for that bit but the led would be off (but nothing was reading it for status so it didn't cause any trouble). Leaving digitalwrite when LEDLINK is defined as this is more efficient and the use case for pwm leds is to find buttons - link indicator would become more ambiguous for no benefit.
* Added settings for ledpwm_on and ledpwm_off with defaults that mimic current digitalwrite function
* Changed ledpoweridx from digitalwrite to analogwrite
* Add commands to change new settings