Updating the Vagrantfile so that builds may be run in an OpenStack
cleanroom instance as well as locally via virtualbox. In order to
properly configure the vagrant instance, a number of environment
variables are utilized. First, all normal OpenStack auth envronment
vars are used to create the instance, and then a host of
GIFTWRAP_OS_* vars are added to control things like the image being
spun up, the networks it is attached to, etc.
A postbuild mechanism is added to allow one to do things like ship
artifacts to a repo, Swift, etc.
Refactor the builders to so that a user may specify one of 2 paths:
system packages or docker containers. This change also encompasses a
bunch of other minor changes. This is being checked in in order to
get some minimally viable changes upstream.