Document how to add options to mandos-client when using dracut
* debian/mandos-client.README.Debian: Remove unnecessary word "simply". Also add instructions on how to add the --connect= options to mandos-client when using dracut. * dracut-module/ask-password-mandos.service ([Service]): Add comments that this file should *not* be modified, and explicit instructions on how to instead add extra options, like --debug, to mandos-client: using a systemd override unit file to set an environment variable.