Since @higebu and @UnicronNL are working on integrating cloud-init, it's time to rethink how we are doing this kind of setup.

Right now, on AWS, the first boot script runs after config is loaded and modifies it with set commands. Due to current config backend limitations it's not exactly safe and needs some caution.
Doing it before it loads and modifying the config file itself is rather safer. This is in the short run.

In the long run, the livecd install script and the password reset script will always have to work on the config file, and the functions they are using and may want to use are essentially the same functions as those in cloud first boot scripts.

If we make a common library that can insert common options into config files, it will save us quite some time and effort adding that functionality I suppose.