Add option to specify source-destination directory

[EnziinSystem]

Thanks for a great project.

I think we should add the option to specify the source directory to the project containing the IOC file and the option to specify the destination directory to contain the generated PlatformIO project code.

The purpose is to avoid a mix of the original code in the STM32Cube project and to avoid duplication of code in the Src folder like the attached image.

A format command like this:

stm32pio new -x /path/to/project.ioc -d /path/to/platformio

Thank you.

[ussserrr]

Duplicate #31

Hello! I see, it is a one of the most requested feature, so I probably going to implement it first.