Create an automated provisioner for HA

Create an ansible playbook that can configure a GitLab instance using PG HA given an inventory file of nodes and variables.

Assumptions:

• Installing to VMs or bare metal

Requirements:

• Non-interactive
• Accepts an inventory and variables
• Idempotent
• At a minimum, should support a cluster with
  • 3 consul nodes
  • 3 database nodes
  • 1 application node
• Support an arbitrary maximum number of nodes for any component
• Installs gitlab-ee package via a configurable repository

Optional/Nice to have:

• Support any platform that omnibus-gitlab supports (will default to Ubuntu 16.04)
• Eventual support other configurations (GEO, Redis HA, etc)