Add but not yet boot nor use LED0 #396

Job	Run time
benchmark_builds-avr (c++14)	34s
benchmark_apple-clang (g++, c++14)	1m 32s
benchmark_apple-clang (g++, c++17)	1m 18s
benchmark_apple-clang (g++, c++20)	1m 18s
benchmark_gcc-clang (g++, c++14)	1m 24s
benchmark_gcc-clang (g++, c++17)	1m 28s
benchmark_apple-clang (clang++, c++14)	1m 40s
benchmark_gcc-clang (g++, c++20)	1m 25s
benchmark_apple-clang (clang++, c++17)	1m 18s
benchmark_gcc-clang (clang++, c++14)	1m 20s
benchmark_apple-clang (clang++, c++20)	1m 18s
benchmark_builds-riscv (c++20)	1m 17s
benchmark_gcc-clang (clang++, c++17)	1m 23s
benchmark_gcc-clang (clang++, c++20)	1m 23s
benchmark_builds-stm32f446 (c++14)	1m 44s
benchmark_builds-stm32f446 (c++17)	1m 52s
benchmark_builds-stm32f446 (c++2a)	2m 25s
benchmark_single-cnl (g++, c++20)	14s
benchmark_single-stm32f429-qemu	59s
benchmark_single-cnl (clang++, c++20)	13s
benchmark_single-stm32f429-qemu-cnl	58s
benchmark_single-stm32f446	33s
	27m 36s

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