drivers: led_strip: add WS2812 I2S-based driver

Add a driver implementation that uses the I2S peripheral.
Based off this blog post:
https://electronut.in/nrf52-i2s-ws2812/



Should help with #33505, #29877 and maybe #47780, as there is no garbage
data at the end of transmissions on nRF52832, and no gaps.

Signed-off-by: Jonathan Rico <jonathan@rico.live>