Add a clear description of the pins of the micro-controller
Context
When working on the device tree, @cfoucher needed a clear description of all the pins of the STM32G474RE and their hardwired connection to the peripherals
Description
There is a general lack of documentation of the hardware on the wiki. We should provide a much clearer picture to our community of what is under the hood.
Solution
Add a page to the wiki describing the hardware in more detail.