Add HA templates to deploy OpenShift on CentOS

These templates are heavily based on the existing OpenShift enterprise
templates for use with RHEL. The OpenShift installer utilized in these
templates has been slightly modified to support CentOS as well as make
the install completely automated (aside from creating districts if so
desired.)

Change-Id: I74acfdd553eb6a4c7ac771b6c0ec6543e1e63ea9