Removed Capsule creation from smoke tests.

Our automation showed that having a `fake` Capsule created (as it was
being done by the CLI smoke tests) was causing a side effect with the
creation of `Repositories` and raising the following error:

::

  ``Action not allowed for the default capsule.``

This pull request removes the capsule creation and usage from existing
CLI smoke tests as well as updates docstrings mentioning the need for
its creation and use everywhere.

This pull request has been tested and it passed with flying colors on `qetello04`.
Merge pull request #1238 from omaciel/remove-capsule-smoke-test

Removed Capsule creation from smoke tests.
fixed failed tests
Merge pull request #1243 from sghai/fix-tests

fixed failed UI tests
Add a test subscribing a system to a content view

Add a new test module: `tests.foreman.api.test_contentview_v2`. Add a test to
this module which does the following:

1. Create an organization, lifecycle environment and content view.
2. Publish the newly created content view.
3. Promote the newly published content view.
4. Create a system which references the organization, lifecycle environment and
   content view.

Update the following methods:

* `ContentView.publish`
* `ContentViewVersion.promote`

Make these two methods raise an exception if an HTTP 4XX or 5XX response is
received, or return decoded JSON data otherwise. Update all usages of those
methods.