added SPI class transmission

[AleksandraFomina]

Added the ability to change the SPI interface pins to which MISO, MOSI and SCK are connected. First we initialize SPI class using SPIClass::SPIClass(uint8_t mosi, uint8_t miso, uint8_t sclk) constructor, more details in documentation https://github.com/stm32duino/Arduino_Core_STM32/wiki/API#built-in-library, and then pass it to SPI initialization function.

    modified:   src/AS5047P.cpp
    modified:   src/AS5047P.h
modified:   src/spi/AS5047P_SPI_Arduino.cpp
modified:   src/spi/AS5047P_SPI_Arduino.h

[jonas-merkle]

Hey @AleksandraFomina 👋🏼
Thanks for your contribution! 🎉
In itself, I find your idea with the expansion of interchangeable SPI pins great. But I'm afraid that with your changes the library loses compatibility with Arduinos that are not based on a STM32 chip. That's why I can't merge your changes at the moment. You would have to separate the implementation for STM32 based chips from the other implementation and use e.g. preprocessor instructions to switch between the implementations. If you have time to come up with something like that it would be great and an enrichment for the library.