[docs] Add more UPK key descriptions (#219)

* Added description of some UPK keys

* More keys described.

This time by experimenting on my PIR-enabled lamp.
Motion is reported correctly via GPIO defined as pirin_pin.
I am also trying to set the PIR sensitivity by applying PWM to the pirsense_pin, and I _think_ it works. More experiments are needed.

* Add UPK2ESPHome link, reformat table

* Add descriptions from BK7231N SDK

* Update docs/resources/tuya-pin-config.md

* Corrected description of cwmaxp

* Description of ambient light sensor values

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Co-authored-by: Kuba Szczodrzyński <[email protected]>