[WIP] WS2812 API rework

[fauxpark]

Description

Some pretty huge changes to the WS2812 API in order to clean a few things up, in particular extrication of the WS2812-specific byte ordering from rgb_led_t.

The ws2812_setleds() API has been replaced with the more RGB Matrix-style init/set_color/set_color_all/flush system, with a new type ws2812_led_t and array of such in each driver to hold the pixel data. The init function has already been implemented, so not much to do there. set_color() and set_color_all() simply assign the RGB components to the given index(es) in the array. flush() mostly contains the existing setleds() functionality, but no longer takes the LED array and LED count as arguments.

Since this is a WIP, a bunch of things will now be broken:

• The LED index adjustment for split boards in rgb_matrix_drivers.c has been removed for the moment, so split WS2812 likely no longer works
• RGBLight (Underglow) has not been touched yet, this code won't compile as it relies on the old API

Testing progress (RGB Matrix):

Driver	Channels	Arch	Board	Status
Bitbang	RGB	AVR	Pro Micro	✔️
Bitbang	RGBW	AVR	Pro Micro	✔️
I2C	RGB	AVR	JJ4x4	✔️
Bitbang	RGB	ARM	Proton-C	✔️
Bitbang	RGBW	ARM	Proton-C	✔️
PIO	RGB	ARM	RP2040 Pico	✔️
PIO	RGBW	ARM	RP2040 Pico	✔️
PWM	RGB	ARM	Proton-C	✔️
PWM	RGBW	ARM	Proton-C	✔️
SPI	RGB	ARM	Proton-C	✔️
SPI	RGBW	ARM	Proton-C	✔️

Testing progress (RGBLight):

• Animations ✔️
• Index Remapping ✔️
• Lighting Layers ✔️
• Clipping Ranges ✔️
• Split ✔️
• Velocikey ✔️

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).