LEDS i2s_data_width config for serial/parallel I2S interface output to multiple GPIO pins

[SpComb]

Separate i2s_data_width -> leds_interface_i2s_options -> parallel from the number of GPIO pins, allowing combinations like:

• serial data output to 8 gpio pins, with each gpio pin outputting the same signal
• parallel 4 data output to 8 gpio pins, with each pair of gpio pins outputting the same signal

The i2s_data_width = 0 default should be compatible with existing config, automatically determining the serial/parallel mode based on the configured number of gpio pins.

Note that serial data output duplicated to multiple gpio pins is significantly faster (FPS) than parallel data output to the same number of gpio pins: 50% utilization vs 65% utilization with 450 LEDs per pin.