Sofle Shield: Add underglow support and increase encoder sensitivity

[infused-kim]

This PR adds underglow support to the sofle keyboard. I used the kyria shield as a reference.

It's been tested on a sofle choc, but the pins are the same on the sofle RGB and there should be no issues.

Board/Shield Check-list

• [x] This board/shield is tested working on real hardware
• [x] Definitions follow the general style of other shields/boards upstream (Reference)
• [x] .zmk.yml metadata file added
• [x] Proper Copyright + License headers added to applicable files (Generally, we stick to "The ZMK Contributors" for copyrights to help avoid churn when files get edited)
• [x] General consistent formatting of DeviceTree files
• [x] Keymaps do not use deprecated key defines (Check using the upgrader tool)
• [x] &pro_micro used in favor of &pro_micro_d/a if applicable
• [x] If split, no name added for the right/peripheral half
• [x] Kconfig.defconfig file correctly wraps all configuration in conditional on the shield symbol
• [x] .conf file has optional extra features commented out
• [x] Keyboard/PCB is part of a shipped group buy or is generally available in stock to purchase (OSH/personal projects without general availability should create a zmk-config repo instead)

[infused-kim]

I have removed the encoder sensitivity commit as per @caksoylar's suggestion and updated the underglow settings for zephyr 3.

Is there anything else that is necessary to be done to get this merged?

[Nicell]

@infused-kim It looks like this branch is failing to build ATM: https://github.com/infused-kim/zmk/runs/6226559733 Is this just because it's so far behind main it doesn't have the updates requiring color mapping?

[Cringely]

Would love for this to be merged, thanks for the effort @infused-kim!

[autoferrit]

I recently acquired this board. I would love to see this merged. I am new to C and ZMK but would like to know if there is anything I can do to help get this merged in.

[SethMilliken]

I've run across a few more instances on various Discord servers of people having issues enabling underglow on their Sofle. Getting these changes landed seems like very low-hanging fruit with no downside. I would be happy to update this PR with the 3.2 pinctrl changes if that helps.

[SethMilliken]

These changes (updated for Zephyr 3.2) have now been merged! This PR can be closed now.