[Feature Request] NUC126 Support

[FlamingCupcake]

Hey there :)
I've begun work on support for the Nuvoton NUC126 family.

I'm basing my work on the current NUC123 code.
Will update with a PR, hopefully in a few days.

[fpoussin]

This looks great, thank you :)

[kovmir]

@FlamingCupcake, what is the current status? This MCU would enable QMK on Ducky One 3.