mandos-ctl: Add new --debug option to show D-Bus calls
* mandos-ctl (PropertyCmd, RemoveCmd, ApproveCmd, DenyCmd): Add debug output (add_command_line_options): Also add "--debug" options. (main): If debug option is set, set logging level to DEBUG. Also add debug output when connecting to Mandos server. * mandos-ctl.xml (SYNOPSIS): Show --debug option where appropriate. (OPTIONS): Document new "--debug" option.