* Add append_hash functionality to k8s module
append_hash adds a hash based on the contents of a ConfigMap
or Secret to the name - this enables immutable ConfigMaps and
Secrets.
* Provide k8s_config_resource_name plugin
The k8s_config_resource_name filter plugin provides a means of determining
the name of ConfigMaps and Secrets created with append_hash
* Add changelog fragment
* fix failing tests
* Update openshift version needed for append_hash
* Provide Kubernetes resource validation to k8s module
Use kubernetes-validate to validate Kubernetes resource
definitions against the published schema
* Additional tests for kubernetes-validate
* Improve k8s error messages on exceptions
Parse the response body for the message rather than returning
a JSON blob
If we've validated and there are warnings, return those too - they
can be more helpful
```
"msg": "Failed to patch object: {\"kind\":\"Status\",\"apiVersion\":\"v1\",\"metadata\":{},
\"status\":\"Failure\",\"message\":\"[pos 334]: json: decNum: got first char 'h'\",\"code\":500}\n",
```
vs
```
"msg": "Failed to patch object: [pos 334]: json: decNum: got first char 'h'\nresource
validation error at spec.replicas: 'hello' is not of type u'integer'",
```
* Update versions used
In particular openshift/origin:3.9.0
* Add changelog for k8s validate change
* Use a sensible default for k8s merge_type
The sensible default for merge_type is `['strategic-merge', 'merge'].
However, we can't make this the default default, as we need to support
users who are using openshift 0.6.0, where the merge_type parameter is
unsupported.
* Refactor k8s test suite for merge_type tests
Allow tests with pre-merge-type openshift and post-merge-type
openshift.
