Convert to stm32f1xx_hal

[dzid26]

Replace "STM32 standard peripheral libraries" ( with modern stm32 hal

STM32CubeMX file should be good starting point to generate code snippets for board.c.

Other approach would be to use CubeMX generated files entirely which would kind of replace board.c and maybe main.c.

Platformio has Hal included (if framework = stm32cube is set), but for safety it is better to include all hal libraries in the repo.