Let's add a proper argparser instance for the 'verify_adm' command,
avoiding situations where the user types 'verif_adm --help' and then
--help is interpreted as the PIN value, removing one more attempt from
the failed ADM1 counter.
Let's use that opportunity to improve the documentation of the command.
Change-Id: I3321fae66a11efd00c53b66c7890fce84796e658
469db9393f