Create a Casper Machine Migrator - Imaging edition

[Daz-wallace]

Runs during Caper Imaging
Runs on the 'before' setting.
Uses osascript to ask for casper authentication details and old Mac details
Find out the Casper url from the netbooted Mac.

Request the URL if not found.
Need to find out what Casper creates as a placeholder during imaging to use to add the stuff to.