[Feature Request] ARM microcontrollers support

[ujl123]

As QMK features grows in size, it feels like avr isn't big enough to fit everything. Would you be able to put out a variant that uses ARM rather than AVR? I know that this will drive up the price but is a great way to future proof the design in terms of firmware support, and for future hardware support if you ever do decide to implement huge qmk features like quantum painter or other big features.

In terms of which to support there are a lot of stm32 that chibiOS supports. Or you could create a design that works with the new rp2040, although only develop branch of QMK supports it.