If we leave the root account w/o a password people will use it that way,
leading to insecure images. Also if we use a default password. So lock
the root account in the templates.
Users will need to do one of these things:
1. Use [[customizations.user]] in their blueprint to configure root or
another user.
2. Use [[customizations.sshkey]] to set a key for root
2. Install a package that configures a user at install time
3. Install a package that sets up a user at boot time (eg. cloud-init)
This also drops the auth line from the kickstart templates, allowing it
to use the default password algoritm instead of md5.
Resolves: rhbz#1626122
