Re-built module loosely based on landcareresearch/puppet-pgbouncer

Changes

• Changed license to MIT
• Added Redhat support
• Changed module so that all config parameters are managed by hash
• Changed module to have templates for each section of config and build file using puppetlabs-concat
• Changed module to use puppetlabs-postgresql module for repo management for pgbouncer
• Set databases and authorized users be be built by defined types so they can be called from 3rd party modules