Standard parse_argv() func is added. --version is now accepted
(previously only the help forms were recognized, via argv_looks_like_help()).
The synopsis changes from "systemd-integritysetup COMMAND ..." to the
standard "systemd-integritysetup [OPTION…] COMMAND …", and the help output
gains an Options section. "help" as the first argument keeps working via
the hidden common help verb.
Previously, we'd just print help and exit with success if no arguments
were given. This seems unexpected and wrong. The program now prints the
usual error message:
Command verb required (one of attach, detach, help).