Removed vagrant provisioning from second stage.

* This will be done in a third stage instead.
Changed ovf prefix to ova.

* Since we're working with OVA's this seemed a little confusing.
Added iso prefix to first stage.

* Since packer is explicit it makes sense for us to be too.
Renamed packer configurations.
Fixed typo in packer configuration.
Added vagrantbox packer configuration.
Added README files for packer configurations.