Integration of STM32WLxx support

[PrometheanDesign]

Is there interest in integrating support for ST STM32WLE5xx into this repository? I would add support for RAK3172 using STM32WLE5CC and SEEED-LoRa-E5 using STM32WLE5JC.
Note that ST calls their radio implementation a "Sub-GHz" radio, and not directly a Semtech radio, although they do license and use the Semtech IP. This is because they also support e.g. Sigfox with this radio.
I am creating this support in my fork of this repository; I will contribute it here if accepted.