Move CI pipeline under StackStorm organization/Remove external CI repo dependency

Currently, our CI pipeline relies on https://github.com/EncoreTechnologies/ci-puppet-python to get the python unit tests bits and blobs.
Ideally, we should either integrate those tests in this repo (if it is the only one under StackStorm org using those tests), or move the repo inside the StackStorm org itself. It helps keep all the bits for build system and CI/CD under one roof.