Pulp - Story #4188: As a Pulp3 user, I have containers
As a Docker user, I have containers
This machinery should run when a release tag is pushed indicating a new release, similar to how plugins publish to PyPI already. When activated it should:
1. Install the plugin on top of the generic, most recent core container.
2. start that container and run pulp-smash tests against it
3. If all the tests pass, publish the container to quay.io with credentials
The credentials need to be configured somehow in the config files.