Use aws-ebs builder to create warden test ami

* Add aws as a packer builder target
* Update the kernel on aws to match the level used locally
* Create vagrant user on aws image
* Setup kernel boot options
  - ec2 uses legacy /boot/grub/menu.lst
  - vmw/vbox uses /etc/default/grub

[#69101842]

Signed-off-by: Michael Fraenkel <fraenkel@us.ibm.com>