Never use the Puppetlabs repos

The Puppetlabs repositories are unsafe for use on any RHEL system.  They replace system / EPEL packages and upgrade to backwards incompatible versions of their own packages without warning.
Update README.md
Merge pull request #2546 from smarterclayton/master

Update readme
Merge pull request #2394 from rharrison10/patch-1

Never use the Puppetlabs repos
WIP Cartridge Refactor - V2 -> V2 Migration

* Add support for Manifest#cartridge_versions
Merge pull request #2547 from jwhonce/wip/v2v2_migration

Merged by openshift-bot
WIP Cartridge Refactor - Update documentation

* Update README.writing_cartridges.md
Merge pull request #2548 from jwhonce/wip/documentation

Merged by openshift-bot