We use a slightly modified version of sphinx-argparse (with patch https://github.com/alex-rudakov/sphinx-argparse/pull/136 applied) in order to generate the command reference for each shell command in the manual. As the upstream repository seems unmaintained for ~2 years, let's use the osmocom 'fork' with that above-mentioned patch applied. Change-Id: I134f267cf53c7ecbc8cbfb33a8766d63bf4a8582