This commit adds support for the STM32G4 series of MCUs, and a board
definition for NUCLEO_G474RE. This board has the REPL on LPUART1 which is
connected to the on-board ST-link USB-UART.
There's no need to have these as separate functions, they just take up
unnecessary code space and combining them allows to factor common code, and
also allows to support arbitrary string descriptor indices.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.
Herwin Grobben
Damien George