And document that one needs to install dependencies before running playbooks.

We do not need the builder functionality from playbook2image and the
resulting image was overly complicated, so this simply builds on
Centos/RHEL.

This patch verifies that logs sent from logging pods can be queried on
the Elasticsearch pod within a reasonable amount of time.

Move task_vars into instance variable so we don't have to pass it
around everywhere. Also store tmp. Make sure both are filled in on
execute_module.

In the process, is_active became an instance method, and task_vars is
basically never used directly outside of test code.

Clean up openshift-checks playbooks

- The referenced issue was closed, seems like a wontfix. Just use the
old syntax and make no noise about it.
- Remove inconsistent use of tags: if tags are passed in the command
line, there is no point in evaluating groups if the checks won't be run
anyway.
- Remove temporal comment, easy to get out of sync.

Make LoggingCheck.run return the correct type

The run method is expected to return a dict. Even though we should not
run LoggingCheck by itself, it is still possible to do it and without
this change we get an unhandled exception.

Clean up unnecessary quotes

Normalize list of checks passed to action plugin

This allows users to pass either a string with comma-separated check
names or a proper list of strings, whatever is more convenient in the
context.

For consistency, the same normalization is applied to the
'openshift_disable_check' variable.

Addresses issue #4967

For now, any version >= 3.6 is handled as if it were 3.6. We may want to
keep that or fine-tune it later.

Also, the ovs_version check is not updated. This is a post-install
health check (does not block install/upgrade) with an update already in
progress so will be addressed there.

The oc client was left out with the move away from playbook2image.
However it is needed in the image for the `oc cluster up` use case for
installing logging or metrics.

This change adds oc via the latest signed and released client RPM,
which requires adding the centos-openshift-origin repo to the image.