Stm32f412zg support

[Emirgkts]

How about stm32f412zg

[fpistm]

Hi,
added to new variant request list #722

Base generated file available here:
https://github.com/stm32duino/Arduino_Core_STM32/tree/main/variants/STM32F4xx/F412Z(E-G)(J-T)

Feel free to add the generic support following the wiki