Switch Vagrant to Ubuntu 64-bit images

VMs will now use the Ubuntu cloud images.

Switched over to the 64-bit images instead of 32-bit.
Management VM setup

Scripted the initial management install for Vagrant so that Ansible is
added there automatically.
Update README for networking and configuration management

Network addressing has changed.

Ansible is now installed with setup.sh during the Vagrant setup for the
management VM.