Practice60 RGB and PWM Backlight (#4929)

Practice60 RGB and PWM Backlight (#4929)

* Update Practice60 to enable RGB via SPI DMA and use PWM backlight breathing

* Correct stm32f103c8t6 flash size in eeprom definition

* Remove unused files and improve ifdef checks

* Update quantum/rgblight.c

Co-Authored-By: awkannan <andrew.kannan@klaviyo.com>
* Update quantum/rgblight.c

Co-Authored-By: awkannan <andrew.kannan@klaviyo.com>
* EEPROM implementation fix and updated p60 code

* Update define

* Remove dead code

* Update keymap to remove test key

* Update keymap again