Added API tests for Docker images.

Added two new API tests for creating repositories that use Docker
content.

**NOTE**: To synchronize a ``Docker`` image, the ``name`` of your custom
  repository **must** match (case matters) the name of the Docker image.
  For example, the
  [WordPress](https://registry.hub.docker.com/_/wordpress/) image would
  require that your repository name be ``wordpress`` as it is displayed
  in its URL.
Merge pull request #1550 from omaciel/docker-api

Added API tests for Docker images.
Added UI tests for Docker images.

Added two new UI tests for creating repositories that use Docker
content. Please see #1550 for more information about naming conventions
for Docker repositories.

Both tests passed against today's nightly build.
Merge pull request #1551 from omaciel/docker-ui

Added UI tests for Docker images.
End to end api smoke test

Steps involved:
1. Create new organization and environment
2. Clone and upload manifest
3. Sync a RedHat repository
4. Create content-view
5. Add repository to contet-view
6. Promote/publish content-view
7. Create an activation-key
8. Add product to activation-key
9. Create new virtualmachine
10. Pull rpm from Foreman server and install on client
11. Register client with foreman server using activation-key
12. Install rpm on client