[2.0.x] HAL for STM32F4 (#10434)

Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.cpp

Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.h

Marlin/src/HAL/HAL_STM32F4/EmulatedEeprom.cpp

Marlin/src/HAL/HAL_STM32F4/HAL.cpp

Marlin/src/HAL/HAL_STM32F4/HAL.h

Marlin/src/HAL/HAL_STM32F4/HAL_Servo_STM32F4.cpp

Marlin/src/HAL/HAL_STM32F4/HAL_Servo_STM32F4.h

Marlin/src/HAL/HAL_STM32F4/HAL_spi_STM32F4.cpp

Marlin/src/HAL/HAL_STM32F4/HAL_timers_STM32F4.cpp

Marlin/src/HAL/HAL_STM32F4/HAL_timers_STM32F4.h

Marlin/src/HAL/HAL_STM32F4/README.md

Marlin/src/HAL/HAL_STM32F4/SanityCheck.h

Marlin/src/HAL/HAL_STM32F4/endstop_interrupts.h

Marlin/src/HAL/HAL_STM32F4/fastio_STM32F4.h

Marlin/src/HAL/HAL_STM32F4/persistent_store_impl.cpp

Marlin/src/HAL/HAL_STM32F4/pinsDebug.h

Marlin/src/HAL/HAL_STM32F4/spi_pins.h

Marlin/src/HAL/HAL_STM32F4/watchdog_STM32F4.cpp

Marlin/src/HAL/HAL_STM32F4/watchdog_STM32F4.h

Marlin/src/HAL/platforms.h