Support SK9822 type LEDs with adaptive brightness control via SPI

[The-Master777]

Summary

Support for SK9822 type LEDs is added with global brightness control feature.

SK9822 type LEDs allow for 5-Bit (32 level) brightness adjustment using simultaneous regulation of R/G/B LED current. This allows for fine granular control of output light levels while maintaining full 8-Bit grayscale resolution. Even though the LED type is generally compatible with APA 102 style LEDs, the constant current regulation function shows compatibility issues with the existing implementation of the APA 102 control protocol.

This PR introduces support for SK9822 devices via SPI. Maximum current (brightness) level is user controllable on the 32 value scale. Also, low luminosity (near black) colors below a user defined threshold are converted such that optimal grayscale resolution is archived on a per LED basis over full brightness range, especially on the low end.

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Docs
• Build-related changes
• Other, please describe:

If changing the UI of web configuration, please provide the before/after screenshot:

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing setups:

The PR fulfills these requirements:

• When resolving a specific issue, it's referenced in the PR's body (e.g. Fixes: #xxx[,#xxx], where "xxx" is the issue number)

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature: Support Current regulated global brightness control on SK9822 leds; not supported with existing the APA 102 device.
• Related documents have been updated (docs/docs/en)
• Related tests have been updated

PLEASE DON'T FORGET TO ADD YOUR CHANGES TO CHANGELOG.MD

• Yes, CHANGELOG.md is also updated

To avoid wasting your time, it's best to open a feature request issue first and wait for approval before working on it.

Other information:

LED Type: SK9822 by DONGGUAN OPSCO OPTOELECTRONICS CO., LTD
Device: SPI
Specsheet: https://www.exp-tech.de/media/pdf/SK9822-EC20-REV-05-EN.pdf

[hyperion-project]

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[Lord-Grey]

Hi @The-Master777
thank you very much for your contribution!

Only minor comments reviewing the code/files provided.

[hyperion-project]

Here is your new link to your workflow artifacts.

[Lord-Grey]

@ The-Master777 Thank you for turning this round quickly. Looks good.

[Paulchen-Panther]

@The-Master777 Ready to merge?

[The-Master777]

@The-Master777 Ready to merge?

Yap, can be merged 👍