Create common prerequisites configuration

[jce-redhat]

First take on splitting out common controller resource configuration that may be used in multiple demo categories. Initially this is the base AWS configuration (VPC, keypair, instance creation) since most of the linux and windows demos require AWS instances which should be created in a common VPC. The controller resource definitions from setup_demo.yml have also been moved into the new common prerequisites setup.yml.

[zjleblanc]

@jce-redhat looks good to me. I don't think there will need to be much if any change to #168 given the template names are unchanged.