Feature: flashstub for RP2040 Flashing #1972

Job	Run time
build-macos (macos-latest)	1m 18s
build-linux (ubuntu-20.04, focal, clang-15, 12.2.Rel1)	3m 45s
build-linux (focal, 96b_carbon)	1m 17s
build-macos (macos-11)	31m 3s
build-linux (ubuntu-20.04, focal, gcc-11, 12.2.Rel1)	3m 53s
build-linux (focal, bluepill)	43s
build-linux (focal, f072)	1m 2s
build-macos (gcc@11)	1m 4s
build-mingw (windows-2022, ucrt64)	2m 54s
build-linux (focal, f3)	51s
build-msvc (meson, windows-2019)	1m 53s
build-macos (gcc@12)	1m 12s
build-mingw (windows-2022, clang64)	2m 39s
build-linux (focal, f4discovery)	53s
build-msvc (meson, windows-2022)	2m 21s
build-macos (gcc@13)	1m 23s
build-linux (focal, hydrabus)	34s
size-diff	52s
build-linux (focal, launchpad-icdi)	1m 2s
build-linux (focal, native)	56s
build-linux (focal, stlink)	1m 8s
build-linux (focal, stlinkv3)	1m 2s
build-linux (focal, swlink)	1m 2s
	1h 4m 47s

Provide feedback