Feature Request: Support for providing script files to post_create_script.

[BHorine24]

It would be nice to be able to pass in a file instead of a list of commands to the post_create_script driver option. This is beneficial when there is a more complex set of actions that must be taken on the machine that would otherwise clutter the kitchen file.

As an extra bonus, it would be even nicer if that script could also be told to run as root (or perhaps sudo is the better way). Right now this hook appears to run as the transport user I believe which in the case of OCI is generally the less privileged OPC user. Being able to run this script via sudo/root would make the script a lot simplier when needing to perform elevated privileges tasks.