Factor out node-value-symbol
Refactor line number in exec-checked-script
Refactor plan-when and plan-when-not

Refactored so that the flag keyword generation is via a function,
which can be redef'd for testing.  Also fixed the line number on
the generated script.
Add create-admin function

This is designed to replace the automated-admin-user function.  It is
more flexible, allowing suppression or forcing of adding the user to
sudo, creation of the user and the user's home directory.  It should
work on systems using pam_ldap and pam_mkhomedir.