Add STM32 U5 Support

[GrantMTG]

This is a new line that STM are pushing. It is very powerful and has excellent prices in quantity. There aren't many chips in distribution yet, but the NUCLEO-U575ZI-Q is available at Mouser. I am evaluating it for a new project and prefer to keep using libusb_stm32 rather than STM's USB.

There may be other boards available, but I am ordering this one:

https://www.mouser.com/ProductDetail/STMicroelectronics/NUCLEO-U575ZI-Q?qs=Wj%2FVkw3K%252BMD4hdUJJxGixg%3D%3D

[GrantMTG]

It looks like STM32H5 is a mainstream equivalent of the low power STM32U5 line. I have not had time to study it yet, but the H5 may have the same USB peripheral as the U5. Here is a link to a nucleo board for it. Since it's new, these boards are just getting into distribution now. The U5 has been around a couple of years.

https://www.futureelectronics.com/p/development-tools--development-tool-hardware/nucleo-h563zi-stmicroelectronics-3172085

[GrantMTG]

There are now "classic" libraries from STM for the U5 and H5. I'm no competent enough to do the libusb_stm32 work, but perhaps this will help someone who can:

https://github.com/STMicroelectronics/stm32u5-classic-coremw-apps

_Classic CoreMW is a collection of middleware stacks and associated applications allowing RTOS management, File System operations and connectivity through USB and Ethernet. It is based on:

ST's proprietary stacks: ST USB Device and ST USB Host
Third parties' stacks: FreeRTOS

This package is exclusively published on GitHub (and is neither available in STM32CubeU5, STM32CubeMX nor STM32CubeIDE available on www.st.com). It contains the integration of the Classic CoreMW stacks with STM32U5 devices, allowing users to get quick access to pre-built projects integrating them._