Enhancement: Add more embedded options for STM32

[Vaishnav-Sabari-Girish]

Hey @marcuspat,

I love the tool and I use it regularly.

When I recently switched from ESP32 to STM32 Based microcontrollers, I noticed a few issues in the ARM Cortex-M section that could be improved :

1. Specifically when I try to use the stm32f1 hal, it does not import the HAL into the Cargo.toml.
2. Also in the .cargo/config.toml file builds for the STM32F4 Series instead of STM32F1

I thought this might be worth reporting.
If possible could you assign this issue to me, I would be happy to work on a fix.

Thanks again for the great tool.